move validators into their own package

also hides the visitor in internal classes to have a cleaner
public interface.
remove rowGranularity from Analysis/AnalyzedStatement

It is not allowed to have a column with a finer granularity
then the table has in the query. So it is unnecessary to
keep track of the max rowGranularity because
tableInfo.rowGranularity() will always have the max
rowGranularity.
docs on storage and consistency
fixup! docs on storage and consistency
Merge pull request #1409 from crate/dobe-consistency

docs on storage and consistency
update es/upstream to include UnicastZenPing change

nodes should accept pings while in disabled state.
fix locking in MergeOperation addRows
fix group by queries on system tables with limit or the same aggregation twice
Merge pull request #1414 from crate/b/fix_group_with_limit

fix group by queries on system tables with limit or the same aggregation...
fix flaky blob coverage
Merge pull request #1416 from crate/m/flaky_blob_coverage

fix flaky blob coverage
do not account ram on projector instantiation
always reset cluster settings after test run
disallow indirect updating of nested clustered by columns
remove a lot of unused code

bye bye!
fix non-distributed group-by plan
fix flaky tests

- use schema for all nested objects if not testing
  dynamic mapping
- use columns of defined schema to avoid dynamic mapping
added note in DEVELOP.rst that test will fail if their is no running network connection
add travis badge to readme
fix travis badge (wrong project ;)