Use Rebar to manage and compile dependencies and optionally compile Zotonic
deps: new z_stdlib
mod_admin_predicate: Fix escaping of translated text in predicate help popup
mod_base: Log error in widgetmanager when evaluating the JSON data attribute fails
mod_base: Remove accidental console.log
doc: fix in docs for split_in and vsplit_in filters.
mod_development: Use z_utils instead of code module.
core: Use the path from code:lib_dir to find zotonic's lib_dir, otherwise use the old method. Fixes #529
Merge branch 'master' into yoonka-add-rebar-compatibility

Conflicts:
	deps/z_stdlib
build: make target 'all' should be default.
Merge pull request #515 from yoonka/add-rebar-compatibility.