Add a coverge script to run tests and produce coverage reports (Fix #245)
Merge pull request #338 from jubianchi/coverage-script

Add a coverage script to run tests and produce coverage reports

## How to use

```sh
$ atoum/scripts/coverage.php -h
# ...
-fmt <xml|clover|html|treemap>, --format <xml|clover|html|treemap>: Coverage report format
-o <path/to/file/or/directory>, --output <path/to/file/or/directory>: Coverage report output path

# Default format is XML (Clover)
$ atoum/scripts/coverage.php -f my/test.php --output coverage.xml
# HTML report
$ atoum/scripts/coverage.php -f my/test.php --output coverage/ --format html
# Treemap report
$ atoum/scripts/coverage.php -f my/test.php --output treemap/ --format treemap
```
Add coverage script in phar stub
Rework coverage script to make it work from phar
Add php 5.6 in allow_failures until we debug the segfaults and php 5.6 gets released
Typo
Fix regex for php version in README.md.

The regex given for testing php versions only supported PHP 5.3.x (x>=3) and 5.4.x.  Now it also supports PHP 5.5.x up to 5.9.x
Merge pull request #343 from nubs/patch-1

Fix regex for php version in README.md.
Clean
Make reports overridable

Only one realtime report is accepted but multiple asynchronous reports can be added
Fix clover report

From http://xdebug.org/docs/code_coverage#xdebug_start_code_coverage: line with a value equal to -2 should not be reported as they have no executable code