destdir support for panda.

there were discussion in IRC and I'm still not very sure if this correct but so far I find it correct.

``` shell
>>DESTDIR=tmp ./bootstrap.pl
==> Bootstrapping Panda
==> Fetching File::Tools
==> Building File::Tools
Compiling lib/File/Find.pm
Compiling lib/Shell/Command.pm
==> Testing File::Tools
t/01-file-find.t ...... ok   
t/02-shell-command.t .. ok   
All tests successful.
Files=2, Tests=9,  3 wallclock secs ( 0.03 usr  0.01 sys +  2.41 cusr  0.10 csys =  2.55 CPU)
Result: PASS
==> Installing File::Tools
==> Successfully installed File::Tools
==> Fetching JSON::Tiny
==> Building JSON::Tiny
Compiling lib/JSON/Tiny/Actions.pm
Compiling lib/JSON/Tiny/Grammar.pm
Compiling lib/JSON/Tiny.pm
==> Testing JSON::Tiny
t/01-parse.t ...... ok     
t/02-structure.t .. ok     
t/03-unicode.t .... ok   
t/04-roundtrip.t .. ok     
All tests successful.
Files=4, Tests=118, 11 wallclock secs ( 0.08 usr  0.03 sys + 10.26 cusr  0.47 csys = 10.84 CPU)
Result: PASS
==> Installing JSON::Tiny
==> Successfully installed JSON::Tiny
==> Fetching Test::Mock
==> Building Test::Mock
Compiling lib/Test/Mock.pm
==> Testing Test::Mock
t/returning.t .. ok   
t/synopsis.t ... ok   
t/with.t ....... ok   
All tests successful.
Files=3, Tests=13,  4 wallclock secs ( 0.04 usr  0.00 sys +  2.62 cusr  0.22 csys =  2.88 CPU)
Result: PASS
==> Installing Test::Mock
==> Successfully installed Test::Mock
==> Fetching panda
==> Building panda
Compiling lib/Pies.pm
Compiling lib/Panda/Ecosystem.pm
Compiling lib/Panda/Common.pm
Compiling lib/Panda/Resources.pm
Compiling lib/Panda/Fetcher.pm
Compiling lib/Panda/Builder.pm
Compiling lib/Panda/Tester.pm
Compiling lib/Panda/Installer.pm
Compiling lib/Panda.pm
==> Testing panda
t/panda/builder.t .... ok   
t/panda/common.t ..... ok   
t/panda/ecosystem.t .. ok     
t/panda/fetcher.t .... ok   
t/panda/installer.t .. ok     
t/panda/tester.t ..... ok   
t/stubs.t ............ ok     
All tests successful.
Files=7, Tests=51, 14 wallclock secs ( 0.07 usr  0.01 sys + 11.41 cusr  0.96 csys = 12.45 CPU)
Result: PASS
==> Installing panda
==> Successfully installed panda
==> Please make sure that /home/nen/contrib/panda/tmp/usr/lib/parrot/5.1.0/languages/perl6/site/bin is in your PATH
```