Sync with EPEL7

- Sync with EPEL7 package
- add numerical prefix to extension configuration file
- add all ini options in configuration file (comments)
- install doc in pecl doc_dir
- install tests in pecl test_dir
- enable ZTS extension
- rebuilt with igbinary support
- add arch specific provides/requires
- add filter_provides to avoid private-shared-object-provides memcached.so
- add minimal %%check