Implement has_userphrase with chewing_userphrase_lookup

[ShengYenPeng]

issue #96

[coveralls]

Coverage remained the same at 89.526% when pulling 7531e86 on ShengYenPeng:master into f353c37 on chewing:master.

[coveralls]

Coverage remained the same at 89.564% when pulling 8a12c0d on ShengYenPeng:master into 52a49da on chewing:master.

[ShengYenPeng]

Hi @jserv , can you give me some suggestion for this pull request?

[jserv]

You have to explain the rationale with the commits and the exact reason why you implement something by deleting the code.

[ShengYenPeng]

The libchewing use internal_has_userphrase to implement has_userphrase by
#define has_userphrase() internal_has_userphrase().

According to czchen's description in issue 96,

After chewing_userphrase_lookup is implemented, has_userphrase shall use chewing_userphrase_lookup instead of libchewing internal functions.

I redefine has_userphrase by
#define has_userphrase() chewing_userphrase_lookup()

I think internal_has_userphrase is a temporary function waiting for chewing_userphrase_lookup,
now that chewing_userphrase_lookup has been implemented, we don't need internal_has_userphrase anymore.

[jserv]

Update GIT commit messages accordingly.

[coveralls]

Coverage remained the same at 89.564% when pulling aa38846 on ShengYenPeng:master into 74feae3 on chewing:master.

[jserv]

@ShengYenPeng : Thanks for your contribution.

[ShengYenPeng]

thanks for your suggestion!