HUE-2043 [core] database options keys have unicode keys

Moved the dictionary logic from librdbms to python_util.
HUE-2068 [infra] Third-party dependencies manifest is excluded from binary distributions
[core] Add python-snappy library
[core] make snappy a first class citizen
[core] add parquet-python library
[core] update parquet-python to use file objects
[filebrowser] read parquet in filebrowser

Rudimentary test for verifying output is not binary
[beeswax] Close HiveServer2 and Impala session command

  e.g. Close all HiveServer2 sessions created by Hue
  build/env/bin/hue close_sessions 0 hive

  e.g. Close all HiveServer2 and Impala created by Hue at least one week ago
  build/env/bin/hue close_sessions 7 all
[desktop] A user can share a document to a group he does not belong too
[filebrowser] Snappy decompression error should throw PopupException
HUE-2012 [core] upgrade django auth ldap
HUE-2012 [core] AD multidomain support

ldap_servers takes precidence over normal ldap config.
backward compatible since original ldap config can be provided.
Add server selection logic on front end.
Split tests by configs: test_ldap_deprecated and test_ldap.
The former will test deprecated configs and the later will test new configs.
The Synchronization middleware will choose the first LDAP Server
config when deciding which server to synchronize with.
HUE-2037 [search] Index a file or hive table easily

Add a collection manually.
Add a collection from a file.
Parse file with APIs.