Convert ST_ConnectedComponents to table function.
Replace unnecessary doc by @inheritDoc.
Remove 'weight' from the required parameters.

Connected components do not depend on weight anyway.
Make orientation optional; finish table fn conv.

I missed a few things when I tried to convert this to a table function:
namely changing the function signature and updating the SQL usage and
javadoc.

In this commit I also make orientation optional and use a
GraphFunctionParser.

I'm currently getting an ArrayOutOfBoundsException because the
ConnectivityInspector is looking for a weight which these graphs no
longer have. (They are weighted graphs, but I removed the calls to
setWeightField().) The problem is that the current version of
GDMS-Topology is a mix between JGraphT and GraphHopper, and the current
graph creators create GraphHopper graphs. My options are:
- Find an easy way to pass unweighted JGraphT graphs to the connectivity
  inspector, or
- Write my own connectivity inspector in GraphHopper-SNA and use that
  instead.
Merge branch 'master' into feature/connected-components-table-fn

This makes the necessary updates for changes in graphhopper-sna.
Put weights back; to be fixed by a future PR.
Remove unnecessary extends.
Rename AbstractExecutorFunctionHelper -> ExecutorFunctionHelper.
Move some methods up to superclass.
Move function helpers to their own package.
Update javadoc.
Add table function helper.
Refactor function helpers.
Merge branch 'refactor/function-helpers' into refactor/ST_ConnComp

The ST_ConnectedComponents refactor will use the new function helpers.
Refactor ST_ConnComp to use new function helpers.
Check for existence of optional argument.
Merge pull request #23 from agouge/refactor/ST_ConnComp

Refactor ST_ConnectedComponents
- Convert ST_ConnectedComponents to a table function and make orientation an optional argument.
- Add FunctionHelpers to facilitate writing SQL functions