(PDB-309) Update config conversion code for Schema 0.2.1

Much of the code for converting user provided config to the internal types (i.e.
"10" to Joda time 10 Seconds etc) is no longer necessary with the new
coerce features of Schema. This commit switches to the new version and
makes the necessary changes to use the coerce feature.
Merge pull request #959 from senior/ticket/master/pdb-309-update-schema-config-conversion

(PDB-309) Update config conversion code for Schema 0.2.1