1037 Guessing process as part of importer
1037 Add config for guessing on import
1037 Sample size to config rather than calculating

For the country guessing, it doesn't make sense to add code to calculate
sample size. So making it configurable. This also makes the developer
aware of the performance implications.
1037 Use config for guessing on import
1037 Rename geometry_guessing to content_guessing
1037 Do not use guessing if disabled by config
1037 Separate ContentGuesser from Georeferencer
1037 Remove ContentGuessser dependency on job
1037 Add some unit tests for the ContentGuesser
1037 Fix some typos in ContentGuesser
1037 Fix georeferencer tests
1037 Simplify is_country_column_type? method
1037 Add zero case tests for the ContentGuesser
1037 Delete some dead code
1037 Modify QueryBatcher to not need an id_column

Modify the QueryBatcher so that it does not require an id_column
parameter. Two different ID's were used, depending on the status of the
table: cartodb_id and ogc_fid.

Now it uses the CTID, that is present on all tables.

See http://www.postgresql.org/docs/9.3/static/ddl-system-columns.html
for more info.
1037 Make kml import tests able to be executed in isolation
1037 Fix test

Fix a georeferencer test that was wrongly fixed at the time by modifying
the expectation instead of actually making the feature work as intended.

Now the feature works as expected, cannot really tell where it got
fixed.
1037 Fix tests broken by modifications in batch queries
Merge remote-tracking branch 'origin/master' into 1037-country-guessing
1037 Extract calculation of country proportion to a method