Remove rel_path causes issues on windows across drives.

Given
	PWD is z:/src/gendev
	RUBY is installed in C:/Ruby193
	path1  = veewee/iso/sol-10-u11-ga-x86-dvd.iso
	path2  = Z:/src/gendev

When
	I run veewee vbox build <definition>
Then
	 I get the following error.

	C:/Ruby193/lib/ruby/1.9.1/pathname.rb:465:in `relative_path_from': different prefix: "" and "Z:/src/gendev" (ArgumentError)
	        from C:/Ruby193/lib/ruby/gems/1.9.1/gems/veewee-0.3.12/lib/veewee/provider/core/helper/iso.rb:116:in `verify_iso'
	        from C:/Ruby193/lib/ruby/gems/1.9.1/gems/veewee-0.3.12/lib/veewee/provider/core/box/build.rb:37:in `build'

Since both a relative and absolute paths should work with curl, md5, and shasum there should be a need to validate a relative path to the iso.
FreeBSD 10.0 RELEASE template

This template boots mfsbsd, which is used to install a minimal base
system onto the disk. The advantages of mfsbsd is that it is
significantly smaller than FreeBSD's disc1 ISO, and already handles many
of the install tasks that the install.sh script of previous FreeBSD
templates would handle.
Install ca_root_nss before fetching from GitHub
Switch over to using binary packages to speed up build
Install all packages in one invocation
Add more ports to the REFUSE
Install dependencies from binary packages
Virtio is now part of the FreeBSD base kernel
Remove call to freebsd-update
Fix package names
Building virtualbox-ose-additions requires /usr/src

So we'll just install from the binary.
Add wait before fetch command
Fix comment
Package of guest additions requires xorg-server - which is not available

As a binary package
Fetch and extract /usr/src and /usr/lib32 to build Vbox-OSE
Add yasm
Move portsclean to after all ports built
Comments
Clean /tmp
Merge pull request #889 from sc68cal/freebsd_10_pkgng

Freebsd 10 Template