Run tests on `make all`.

Also make sure that the needed source files are present
when running the test suite.
Add failing test for #155.
Merge branch 'master' of https://github.com/quasiconvex/erlydtl into quasiconvex-master
Update README to reflect new stable branch usage (#154)
Add list indexing incompatibility note (#155)
Update NEWS.
Setup development branch.

Dependencies are not pinned down, but follow their
respective development branches.

Our version is generated on build time using git
(e.g. it requires a git cloned repository to build).

The NEWS files is flushed, so it only contains the
bullets of news since the last release merge.
New option for 0-based list access (fixes #156)
Fix tuple access (related to #155)
New option for 0-based tuple access (#156)
Flush NEWS.

As the NEWS items are merged with stable and released,
they are dropped from the master branch to keep it
clean and tidy around here..
erlydtl_beam_compiler: clean up meta forms.

this makes the code so much more readable, and easier to tweak.
Fix #61: add compile options default_vars and constants

vars is deprecated (aliased to default_vars).

The `forloop` variable is now marked as a reserved internal variable name,
and can't be used default/constant variable.
clean up #ast_info.pre_render_asts

it is no longer used.
erlydtl_beam_compiler: refactor custom_forms for readability..
fix #157: avoid broken R16B03
R15B03-1 not available on travis..
drop bitdeli badge.
avoid R15B and R15B01

merl depends on changes in erl_syntax introduced in R15B02: https://github.com/erlang/otp/commit/53746070b5de7d1e9f809d516648948b0a246561
Run merl tests together with erlydtl tests.

Avoid always running the merl tests when only compiling.

cf. richcarl/merl#6