fix($compile): reference local in isolate scope

This was really corner case:
Watcher needs to return changed value, to notify that model might have changed and one more $digest cycle needs to be performed.

The watcher, that takes care of reference binding into an isolate scope ("="), did not return changed value, if the change was from the isolate scope to the parent.

If any other watcher returned change, it worked fine, as this change caused re-digest.

Closes #1272
chore: add travis config
docs(downloading): update the downloading docs
fix(doc): disable directory listing in docs.angularjs.org
chore(Rakefile): use exec for webserver

exec unlike system replaces the current process. this way when we kill
the webserver process we don't get scary looking 'rake aborted' error
chore(Rakefile): misc_options should support + -> , conversion
chore(test): add junit config for testacular
chore(Rakefile): paralelize closure compilation

this speeds up the build by paralelizing closure compilation (the slowest
piece of the build process)

before:

real  0m14.372s
user  0m31.649s
sys   0m1.006s

after:

real  0m8.191s
user  0m40.473s
sys   0m1.378s
chore(Rakefile): tune JVM for closure compiler

Using the client VM and forcing 32bit mode gives us huge perf boost.

before:

reali   0m8.173s
user    0m39.984s
sys     0m1.408s

after:

real    0m3.000s
user    0m12.687s
sys     0m0.852s
chore(Rakefile): remove test_out dir when cleaning
docs(tutorial): replace JsTD with Testacular + drop snapshots

JsTD references have been replaced with Testacular stuff.

snapshots are PITA to maintain so I'm dropping them, everyone loves the Git
version anyway.
chore(jstd): remove JsTestDriver from our repo

Testacular FTW!
chore(jasmine): remove Jasmine from our repo

it's bundled with Testacular, so we don't need it here
chore(validate-commit-msg): allow * and - in scope string
chore(jstd-scenario-adapter): remove from our repo

since we don't need the adapter for JsTD (testacular contains its own),
I'm removing this dead code.
docs(contribute): add visible link to github project
docs(contribute): add CLA note to code submission section
chore(check-size.sh): fix rake target
doc(faq): Fix minor spelling and wording errors
doc(faq): Add Common Pitfalls section

Describes several common pitfalls new users of Angular fall into that
I've observed in #angularjs.