Make third wkt-parametr (axis-order=long-lat) optional for MariaDB compatibility

[Surzhikov]

Unlike MySQL, the WKT-input spatial analysis functions in MariaDB (like ST_GeomFromText and ST_DISTANCE) do not take an options parameter: https://mariadb.com/kb/en/st_geomfromtext/

For this reason, we should get an SQL error, while saving the model with spatial fields:
SQLSTATE[42000]: Syntax error or access violation: 1582 Incorrect parameter count in the call to native function 'ST_GeomFromText'

A similar issue was in grimzy/laravel-mysql-spatial and it was fixed by pull request grimzy/laravel-mysql-spatial#152

[Surzhikov]

Adding pull request #51