Introducing HBase 0.95 profile

Guys,

with many thanks to Jean-Daniel here's the first rough cut
of the HBase 0.94/0.95+ profiles I was talking on the phone
about. Wit this last commit in place you can either build
hbase-indexer in the usual way, or you can:
```
mvn clean compile -Dhbase.api=0.95
```
to enable the HBase 0.95 compatible build. 

The way it is implemented is that hbase-sep-imp has been
split into HBase specific parts (0.94 and 0.95+) with all
the common files still in place.

I've also introduced a bit of a poor man's shimming layer 
in HBaseShims to paper over silly differences between
HBase 0.95+ and HBase 0.94.

Please let me know if you like the general direction.

Thanks,
Roman.