Add custom config for PHP modules

Sets up and enables configuration for php 5.4 modules. It accepts an
optional priority parameter.

Small changes are required to accomodate these changes to 5.4, as it
changes slightly the way of handling the modules.
Manage configuration of extensions.

PHP can be compiled with `--with-config-file-scan-dir` which enable
adding all INI files from a given directory - configurable by
`hwr_path_php_mods_enabled` variable. You can get loaded ini files list
using `php_ini_scanned_files()` function.

Instead of controlling priority and making it a necessity (and a pattern
for file names) for extensions, the user should control the file names
which doesn't enforce a file name for him and also enables him using a
priority system.

The tasks to control configuration were moved to the PECL YML and an
option to remove all unmanaged configuration files is added.
Merge pull request #25 from augustohp/add_module_config

Add additional INI configuration management