Initial work cleaning up op table
Move all unary operators to new schema
Move comp_op to the new table
Move and and or operators to the new table
Group arrow-like ops together
Move operator table clean up
Move ++, --, ** and // to new table
Finish operator table clean up
Update CHANGELOG after clean up on the operators table
by making it sane and clean in case we want to add
custom operators in the future.

The operator table with suggestions of extension points
(not yet implemented) can be found in the elixir_parser.yrl
file.

The only backwards incompatible change is the precedence
of the operators used by the Bitwise module.
Clean up defdelegate docs
Inspect module before printing, closes #1309
Add unquote: true support to Macro.escape
Allow :binding as an option in quote

This commit also adds Macro.expand_once/2 and Macro.expand_all/2.
IO.ANSI now uses binding
Record type should be private by default, closes #1288
Rename sigils from __ to sigil_$, closes #1301
Update docs for Record.import/2
Use semver for development version

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>
Release v0.9.3
Bump to v0.9.4-dev