Use hardcoded version on elixir.app.src for now

Related to #808
Allow building Elixir on R16
R16A fixes
Improve how aliases for defmodule are generated
Merge pull request #813 from alexrp/master

Fix #812: Write a trailing newline character to the Mix lockfile.
Take into account Erlang may pass line numbers as none
Reduce vars footprint in case/receive clauses
Fix unused vars warnings
Better error reporting for invalid type specifications

Closes #818
IO.ANSI.escape shouldn't emit a reset sequence if no ANSI sequence was emitted

Closes #807
Expand current module macros with Macro.expand, closes #815
Update CHANGELOG
Don't emit ANSI sequence escape codes in shell in OTP prior to R16
Better error reporting for invalid ANSI escape sequences
Add missing specification for IO.ANSI.terminal?/1
Minor IO.ANSI.terminal?/0 documentation improvement
Use tag from VERSION on package.exs
Implement as_boolean/1 type

Closes #798
Tidy up and clean up quote API, closes #814
Refactor aliases handling