Remove astor from requirements-dev.txt.

This is not necessary since 870c136.
Hy reader macros #377

Added first iteration of reader macros
Refactored defmacro and defreader
Added test inn hy/tests/lex/test_lex.py
Added new test in hy/tests/native/tests
Added new test in hy/tests/macros.

changed the error given in the dispatch macro and added some handling for missing symbol and invalid characters
Merge branch 'reqs-astor' of https://github.com/berkerpeksag/hy into berkerpeksag-reqs-astor
Nuke the rply git checkout from tox.ini