[Proj] Use of SQLite

[Martin Desruisseaux]

For what it is worth, compatibility of EPSG terms of use with open
source licences has been discussed within Apache too [1]. The resolution
has been to provide EPSG data as a separated download in a "non-free"
group. In Apache SIS we provide a small list of hard-coded CRS covering
a few well-known cases [2]. If the user ask for another CRS, the error
message point to a web page with instruction for adding the EPSG database.

    Martin

[1] https://issues.apache.org/jira/browse/LEGAL-183
[2] http://sis.apache.org/apidocs/org/apache/sis/referencing/CRS.html#forCode-java.lang.String-