sourceMap support (wip)

added concat.coffee - manage compiled sources concat. produce map

source_file handle new compiler result : {compiled, map}

source_file keep copy of compiled source and have 'sourceMap' property
commonJs wrapper correctly setup input map, removed concat.coffee, (in generate)
keeping track of what files are compiling so that things aren't recompiled fifty bajillion times
fix sourcemaps for custom module definition
Merge pull request #566 from es128/fix-sourcemaps

fix sourcemaps for custom module definition
Merge pull request #563 from bolster/multiple-compile-fix

Multiple Recompilation
merge sourcemap from upstream
bad parsing of compilers response
Merge pull request #567 from plepers/sm_fixes

SourceMaps - bad parsing of compilers response
compilers now must return {code, map} when sourcemap is enabled (instead of {compiled, map} )
Merge pull request #569 from plepers/sm_fixes

compilers must return {code, map} when sourcemap is enabled
Make FileList lists objects instead of arrays.
Merge branch 'master' of github.com:brunch/brunch
s/minifier/optimizer/g

to eliminate any future confusion regarding the term change

still backward-compatible
Merge pull request #571 from es128/master

Change `minifier` to `optimizer` consistently
Merge remote-tracking branch 'upstream/master'