normalize version numbers and use App::RewriteVersion in tooling

[Grinnz]

Fixes #303

• dist_version doesn't need to be specified in Build.PL, Module::Build can retrieve it from dist_version_from (which will default to lib/perl5i.pm based on the module_name).
• the 'use version' and explicit version object construction isn't necessary on 5.10+ where version.pm is core. also, App::RewriteVersion can't rewrite those anyway
• App::RewriteVersion does not support underscore versions in tuples. This is by design, because these are pretty crazy and you would need to depend on version.pm 0.9915 to get consistent behavior for them. App::RewriteVersion can pass a 'is_trial' option to rewrite_versions, but that will only append a # TRIAL comment to the version declarations, assuming you will mark the release as a trial yourself. (you can do this by adding -TRIAL to the tarball name just before the file extension, and by setting a release_status other than stable.)
• Module::Build unfortunately has no built in way to specify App::RewriteVersion as a develop prereq, but the error message should hopefully make it apparent when it's needed.
• changed admin shebangs because my perl is not in /usr/bin :)