Let `perlbre alias help` means `perlbrew help alias`.
Preserve the execution order for `exec` command if `--with` option is given.

Even if the content contain duplicate items.

Closes GH #297
Remove the `uniq` subroutine, which is not used in the pm code anymore.
require the latest version of CPAN::Perl::Releases
Unalias grep command

Escape sequences are written to '$PERLBREW_HOME/init' if user defines
grep alias like "alias grep='grep --color=always'".
Merge pull request #307 from syohex/unalias-grep

Unalias grep command
remove debug-purposes statement.
Fix 'list-modules' when current env is with a lib, so that the output correctly list all modules inside a lib.
update changelog
Merge branch 'release/0.61' into develop

Conflicts:
	Changes
update change log.
version bump.
rebuild 0.62 standalone executable.
Merge branch 'release/0.62'
Merge branch 'release/0.62' into develop
Use opendir+chdir to change back to the original directory.

This removes the direct dependency on Cwd module.
Try to remove the direct dependency on PathTool.
rebuild
sub assert_installation -> sub assert_known_installation

fix for this problem:

perlbrew alias create perl-5.14.4 ops
Can't locate object method "assert_known_installation" via package "App::perlbrew" at /loader/0xd155d0/App/perlbrew.pm line 42.

Seemed to me that the subroutine was defined as 'assert_installation' but used as 'assert_known_installation'.  So I changed
the subroutine name to 'assert_known_installation' since it was called that multiple times.
require the core Cwd early to avoid arch conflict in PERL5LIB

The issue is discovered @dagolden in GH #297

Basically we need to ensure the core version of Cwd is loaded
instead of its twin brother in PERL5LIB, which might be built
with different archname.

While using lib::core::only works with fatpacked executables,
it breaks CPAN installation. This change with several others
beforhand should work for both scenario. However at some point
it might be more convienent to release the fatpacked execuatable
to CPAN too.