fix deletion of partitioned tables

* when the WHERE clause had no match all partitions were deleted
Merge pull request #1217 from crate/m/delete_partition_fix

fix deletion of partitioned tables
use partition ident in copy from

was ignored before and import was done into `null`
partition.

This fixes https://github.com/crate/crate/issues/1215
fix lt and gt operator
fix update on partitioned tables
added test for partitioned update with not and conjunction
implemented partition visitor

and use it in DataStatementAnalyzer.generateWhereClause(...)
for compatibility reasons. should be moved to DocTableInfo.getRouting(WhereClause)
resolve partitions using normalizer and partitionExpression
implemented where clause splitter
Merge pull request #1198 from crate/m/where_splitter

implemented where clause splitter
move new relation classes into metadata package
add a class to generate joinRelations from a list of analyzed relations

to rewrite select * from a, b -> select * from a cross join b
(and possible other join types in the future)
renamed visitRelation
nested loop implementation
order by splitter
Merge pull request #1204 from crate/m/nestedloop

nested loop executor
Merge pull request #1207 from crate/h/orderby-splitter

orderby splitter
add relation attribute to SelectAnalysis

The AnalyzedQuerySpecification isn't fully integrated into
the Analyzer yet, but this commit should make it possible to
already adopt parts in the planner.
add relation symbol
remove integer, offset and having from AbstractDataAnalysis