fixing :libs filtering bug

I just noticed this when I was going through the code.

The filtering of js-file build dependencies to keep built files out of
the dependancies wasn’t working. This patch fixes it.

To cause the bug just set :libs to your output-dir and look at the
dependency mtimes list. You will see that it contains all the compiled
js files.

This patch fixes that.
Optimizing environment reload

Currently working on clj files in auto mode is difficult as it causes a
complete rebuild from the ground up external dependancies do not need
to be recompiled.

This commit demonstrates a reload procedure that is equivalent to the
current one but is a lot faster because because all compiled
dependancies are not deleted.

The method employed here touches the compiled target files for all cljs
sources (including crossover sources) with an old modification time.
This forces the compiler to rebuild all local class source files.

External dependancies cannot rely on the current project so there is no
need for them to be recompiled.

This patch is still a blunt way to handle this but it is tremendously
more efficient for the most common cases.
fix reloading of clj files in cljs dirs

cljsbuild “auto” produces different results than “once” if a clj file
that is a dependency of a clj based macro file.  This is because
non-macro clj files are not reloaded on change.

The issue behind https://github.com/emezeske/lein-cljsbuild/issues/210
appears to have been resolved as of clojurescript 2202.

I removed the guard that only allows .clj files that contain macros to
be reloaded.  I have tested this and it works pretty darn good :)
Merge branch 'optimize-reload' of https://github.com/bhauman/lein-cljsbuild
Merge branch 'clj-reloading' of https://github.com/bhauman/lein-cljsbuild

Conflicts:
	support/src/cljsbuild/compiler.clj
Merge pull request #347 from bhauman/js-filtering

fixing :libs filtering bug
1.0.4