Added getters for fs.path, fs.mount and fs.dev in node stats api

Closes #4004
explicitly enable http when running plugin tests

add an option to force a setting when building a node, overriding if its explicitly set as system property
Also resend shard started message if shard state is in POST_RECOVERY and master thinks it's initializing.

Closes #4009
Add back hashed BytesValues optimization that got lost in a previous commit.

Some FieldData consumers require hash values per byte. We provide an optimization
that allows to cache the hashes internally if the consumer knows that they are needed
this optimization got lost in a previous commit. This commit adds them back and folds
the dedicated method into AtomicFieldData#getBytesValues(true|false)
minor improvement to FullRollingRestartTests failure output
throw index already exists failure when it exists as alias on creation
make sure to throw the already exists exception, so when indexing into an alias, and it has not propagated yet through the cluster state, it will end up being ignored if it already exists
[DOCS] Fixed a typo
[DOCS] Added a version flag to percolation
RegexpQueryBuilder now implements MultiTermQueryBuilder

This allows the RegexpQueryBuilder to be used in span queries

Added tests for all span multi term queries.
Also updated the documentation and removed mentioning of numeric range
queries for span queries (they have to be terms).

Closes #3392