MySQL connection dsn, charset support

 - added charset support for MySQL dsn string
 - added charset parameter to the phinx configuration
 - updated configuration documentation
postgres schema
fixed phunit configs
Added signed variable to mysql table
removed stray semicolon
corrected testAddStringColumnWithSiqngedEqualsFalse test
restructured tests so expected & actual are the correct way around
Added information about PDOs
Update migrations.rst
install improvements
#170 : Try to locate phinx.php

If no config file passed as arg, try phinx.yaml and fallback to
phinx.php. Exception still ask for phinx.yaml as it is intended
behavior.
use `empty` to check $options['port']

i want use the `port: %%PHINX_DBPORT%%`, but other people maybe like the default port,
so just given a empty port config.
Fix typo in configuration.rst

devlopment -> development
Merge pull request #189 from 3onyc/patch-1

Fix typo in configuration.rst devlopment -> development
Added valid column types list

I always have to go routing through the source code to find this, so thought it would be useful to include in the main documentation.
Minor whitespace cleanup
Merge pull request #190 from coatesap/0.3.x-dev

Added valid column types section
install improvements
fix copyright
Merge branch '0.3.x-dev'