change to allow an installation name like perl-*

because plenv global command eliminates 'perl-' prefix from the indicated name,
you fail to switch perl version if you installed it with a name like perl-5.16.3
Use --mirror-only for migrate-modules

This would be much faster since it won't hit cpanmetadb for each module
when there're hundreds of modules to migrate.
Add 'version' file to gitignore
Merge pull request #18 from miyagawa/migrate-mirror

Use --mirror-only for migrate-modules
Merge pull request #14 from koko-u/fix_installation_name_handle

could not use an installation_name like 'perl-5.16.3'
Merge pull request #19 from miyagawa/gitignore-version

Add 'version' file to gitignore
remove .perl-version from repo closed #20
plenv --version. closed #17
minil build
Checking in changes prior to tagging of version 1.4.12.

Changelog diff is:

diff --git a/Changes b/Changes
index afa384a..4e3224a 100644
--- a/Changes
+++ b/Changes
@@ -2,6 +2,11 @@ Revision history for Perl extension App::plenv

 {{$NEXT}}

+1.4.12 2013-04-15T05:43:50Z
+
+    - Added `plenv --version`
+      (Suggested by miyagawa++)
+
 1.4.11 2013-03-31T03:43:53Z

     - pass test option to Perl::Build
Merge branch 'master' of github.com:tokuhirom/plenv
chmod +x
Do not handle `plenv exec perl --version` in core.
oops
Gah!
oops
Search only plenv PATH if current environment is not "system"(#21)
Merge pull request #24 from syohex/fix-which

Search only plenv PATH if current environment is not "system"(#21)
minil migrate
Spelling fix