Add JSON to externs

Since JSON is available everywhere, add JSON to the default externs list.
Remove cruft related to bounce-indent
Fixup whitespace
Stop emacs from hanging after split strings

close #81
Prevent splitting string after backslash at end of line

close #80
Customize indentation level of continued expressions

Apply https://github.com/witterk/js3-mode/commit/35af217ebfc8e627856b955df0fb9bec2228dfea by witterk
Add js3-boring-indentation

See http://stackoverflow.com/questions/10906228/emacs-problematic-javascript-indentation

Apply https://github.com/witterk/js3-mode/commit/cb3d2796987c5e4a6a2039b87889e6b30840d5d0
Add js3-manual-indentation option

Per sanbor's suggestion

See #39
Add new test case
Add test for issue #28 @emallson
Fix indentation of block comments

close #82
Merge remote-tracking branch 'upstream/master'

Conflicts:
	js3.el
	lib/js3-indent.el
modified README