[CORE] fix maskLevel is set with group id while it should be group level

See #144
Merge pull request #159 from ozon/improvements/find_plugin_cfg

[core] Try to guess plugins configuration file if missing or incorrect
Merge pull request #161 from FenixXx/release-1.10

[iourt42] updated Radio call regular expression
Merge pull request #150 from thomasleveil/fix/group_level_in_mask_level

fix maskLevel is set with group id while it should be group level
add json output
reformat code to be closer to PEP 8
Merge pull request #160 from ozon/features/help-json_output

[core] add json output for autodoc
[STORAGE] refactored syntax: get close to PEP8
[STORAGE] fixed impossibility to retrieve group 'guest' from the storage layer
[TESTS] update tests to comply with the new getGroup() storage method
Merge pull request #163 from FenixXx/release-1.10

[STORAGE] fix impossibility to retrieve group 'guest' from the storage layer
update version to R21
admin.yell is back since R21

- remove changes from ca533a24226ca557aa2245c98ab3d7f0d9e43293
use 'teamFactionOverride' instead of teamXFactionOverride'

vars.team1FactionOverride, ..., vars.team4FactionOverride was in R19 replaced by 'vars.teamFactionOverride'
Merge pull request #164 from ozon/improvements/bf4_parser

[BF4] R21
XLRstats v3.0.0-beta.3 - Moved minPlayers checking to XLRstats plugin, obsoleted the subPlugin: XLRstatsControllerPlugin
[TESTS] fix mysql test database name cannot be changed
[TESTS] add Drone.io configuration file
[TESTS] fix xlrstats tests
[TESTS] change BF4 test_map_unknown to it does not depend on the existing maps

This help maintaining the tests while new maps are added to the game