Add license

Always attempt to re-link, even on failures. Closes #2.

Updated "installed" command to also match standard php package.

Since older PHP versions are now keg-only, they require the --force flag to link. Relates to #3.

Updated "installed" command to match new PHP package name format.

Deploy a tarball.

Added some basic documentation.

Testing a lack of script section in Travis config.

Adding travis deploy configuration.

Implemented upgrade command.

Extension commands are probably not necessary.

Implemented install command.

Only unlink if linked.

Implemented the extension installed command

Updated README.