Refactor search logic to support regex

`crew search` use to only return a single result if your query string
matched a package name exactly.

`crew search` now supports regex.

chronos@localhost / $ crew search ^lib
Found libpcap, version 1.8.1
Found libjpeg, version 9.1
Found libunwind, version 1.1
Found libxslt, version 1.1.28
Found libffi, version 3.0.13-1
Found libssh2, version 1.4.3
Found libtool, version 2.4.6
Found libpipeline, version 1.4.1
Found libevent, version 2.0.22
Found libxml2, version 2.9.2
Found libgd, version 2.0.33
Found libtiff, version 4.0.7
Found libpng, version 1.6.26
Found libsigsegv, version 2.10

crew

@@ -153,6 +153,14 @@ def search (pkgName, silent = false)
   abort "Package #{pkgName} not found. :(".lightred
 end
 
+def regexp_search(pkg_name)
+  results = Dir["#{CREW_LIB_PATH}packages/*.rb"] \
+	  .select  { |f| File.basename(f, '.rb') =~ Regexp.new(pkg_name, true) } \
+	  .collect { |f| File.basename(f, '.rb') } \
+	  .each    { |f| set_package(f) }
+  abort "Package not found :(" unless results.length > 0
+end
+
 def help (pkgName)
   case pkgName
   when "build"
@@ -663,7 +671,7 @@ when "help"
   end
 when "search"
   if @pkgName
-    print_package @pkgName, true
+    regexp_search @pkgName
   else
     list_packages
   end