--exact option for search (just like in eix util)

usage:

``` shell
Asylum entropy # equo s mono
╠  @@ Searching...
╠      @@ Package: app-leechcraft/lc-monocle-0.5.90-r1 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 0.5.90-r1 ~ tag: NoTag ~ revision: 0
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Homepage:      http://leechcraft.org/ 
╠          Description:   Monocle, the modular document 
╠                         viewer for LeechCraft. 
╠          License:       GPL-3
╠      @@ Package: dev-dotnet/mono-addins-0.6.2 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 0.6.2 ~ tag: NoTag ~ revision: 0
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Homepage:      http://www.mono-project.com/Mono.Addins 
╠          Description:   A generic framework for creating 
╠                         extensible applications 
╠          License:       GPL-2
╠      @@ Package: dev-dotnet/mono-nat-1.1.0 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 1.1.0 ~ tag: NoTag ~ revision: 0
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Homepage:      http://projects.qnetp.net/projects/show/mono-nat 
╠          Description:   Mono.Nat is a C# library used for 
╠                         automatic port forwarding, using 
╠                         either uPnP or nat-pmp. 
╠          License:       MIT
╠      @@ Package: dev-dotnet/monocalendar-0.7.2 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 0.7.2 ~ tag: NoTag ~ revision: 1
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Homepage:      http://www.monocalendar.com/ 
╠          Description:   iCal clone for .NET 
╠          License:       GPL-2
╠      @@ Package: dev-dotnet/monotorrent-0.80 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 0.80 ~ tag: NoTag ~ revision: 0
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Homepage:      http://projects.qnetp.net/projects/show/monotorrent 
╠          Description:   Monotorrent is an open source C# 
╠                         bittorrent library 
╠          License:       MIT
╠      @@ Package: dev-lang/mono-2.10.9-r2 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 2.10.9-r2 ~ tag: NoTag ~ revision: 0
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Homepage:      http://www.mono-project.com/Main_Page 
╠          Description:   Mono runtime and class libraries, 
╠                         a C# compiler/interpreter 
╠          License:       BSD-4 GPL-2 GPL-2-with-linking-exception IDPL LGPL-2.1 MIT Ms-PL NPL-1.1
╠      @@ Package: dev-lang/mono-basic-2.10 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 2.10 ~ tag: NoTag ~ revision: 0
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Homepage:      http://www.mono-project.com/VisualBasic.NET_support 
╠          Description:   Visual Basic .NET Runtime and Class 
╠                         Libraries 
╠          License:       LGPL-2 MIT
╠      @@ Package: dev-util/mono-debugger-2.10 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 2.10 ~ tag: NoTag ~ revision: 2
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Homepage:      http://www.mono-project.com/ 
╠          Description:   Debugger for .NET managed and unmanaged 
╠                         applications 
╠          License:       GPL-2 MIT
╠      @@ Package: dev-util/mono-tools-2.10 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 2.10 ~ tag: NoTag ~ revision: 1
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Homepage:      http://www.mono-project.com/ 
╠          Description:   Set of useful Mono related utilities 
╠          License:       GPL-2 MIT
╠      @@ Package: dev-util/monodevelop-3.0.2-r1 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 3.0.2-r1 ~ tag: NoTag ~ revision: 1
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Homepage:      http://www.monodevelop.com/ 
╠          Description:   Integrated Development Environment 
╠                         for .NET 
╠          License:       GPL-2
╠      @@ Package: dev-util/monodevelop-database-3.0.2 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 3.0.2 ~ tag: NoTag ~ revision: 1
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Homepage:      http://www.monodevelop.com/ 
╠          Description:   Database Browser Extension for 
╠                         MonoDevelop 
╠          License:       GPL-2
╠      @@ Package: dev-vcs/monotone-1.0-r4 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 1.0-r4 ~ tag: NoTag ~ revision: 0
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          1
╠          Homepage:      http://monotone.ca 
╠          Description:   Monotone Distributed Version 
╠                         Control System 
╠          License:       GPL-2
╠      @@ Package: media-gfx/paint-mono-0.1.63 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 0.1.63 ~ tag: NoTag ~ revision: 0
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Homepage:      http://code.google.com/p/paint-mono/ 
╠          Description:   An unofficial effort to port Paint.NET 
╠                         3.0 to Linux using Mono. 
╠          License:       CCPL-Attribution-NonCommercial-NoDerivs-2.5 MIT
╠      @@ Package: net-dns/avahi-mono-0.6.31-r1 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 0.6.31-r1 ~ tag: NoTag ~ revision: 0
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Homepage:      http://avahi.org/ 
╠          Description:   avahi mono module 
╠          License:       LGPL-2.1
╠      @@ Package: virtual/monodoc-2.10 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 2.10 ~ tag: NoTag ~ revision: 0
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Description:   Virtual for monodoc 
╠          License:       
╠      @@ Package: www-apache/mod_mono-2.10 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 2.10 ~ tag: NoTag ~ revision: 0
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Homepage:      http://www.mono-project.com/Mod_mono 
╠          Description:   Apache module for Mono. 
╠          License:       Apache-2.0
╠   Keywords:  mono
╠   Found:     16 entries
Asylum entropy # equo s -e mono
╠  @@ Searching...
╠      @@ Package: dev-lang/mono-2.10.9-r2 branch: 5, [sabayonlinux.org] 
╠          Available:     version: 2.10.9-r2 ~ tag: NoTag ~ revision: 0
╠          Installed:     version: Not installed ~ tag: n/a ~ revision: n/a
╠          Slot:          0
╠          Homepage:      http://www.mono-project.com/Main_Page 
╠          Description:   Mono runtime and class libraries, 
╠                         a C# compiler/interpreter 
╠          License:       BSD-4 GPL-2 GPL-2-with-linking-exception IDPL LGPL-2.1 MIT Ms-PL NPL-1.1
╠   Keywords:  mono
╠   Found:     1 entry
```