major change in PMS handling

PlexAPI
- g_PMS to store server properties per aTV
- declare, search, access functions (class-like?)
- discover: checks GDM + MyPlex
- intermediate XMLFromMultiplePMS: add PMS address, similar to aTV
WebServer
- removed: try to discover
XML_converter
- discover whn aTV app starts - ie PlexConnect.xml is requested
- handle PMS() data in URL, IMAGEURL
- rewritten PMDCOUNT, PMSNAME
Settings
- removed "toggle PMS"

Known issue…
when cancelling out/at the end of video replay, the PrePlayScreen is
not found ->PMS unknown.
fix for commit #401: updatePag() contains correct URL to provide PMS address
fix for commit #401: PMS search.
a bunch of changes addressing the "accesstoken" issue
couple of fixes and improvements

Dahlgren's commits:
- 59d1163bc7 - Fixed key typo
- 0c3dfb381b - Make sure MyPlex PMS is updated within the last two days
- 4b5f21cd3 - Handle error where thre are no local or MyPlex PMS present
Thanks!

force discover/PlexGDM when signing into/out of Myplex
add MyPlex template to collect all remote/shared servers
send server-based accesstoken to .js instead of MyPlex authorisation.

- add new special char to {{VAL}}: % to access PMSProperty, might even
be used to replace {{PMSNAME}}, {{ADDR_PMS}}
- rework application.js to better show we are using server-based
accesstoken
add setting for bitrate limit of remote/shared MyPlex servers
decouple PMS discovery from requesting PlexConnect.xml
optimization: don't add '/PMS( )' to URL if PMS is unspezified
grab and store name/uuid for manual defined server, too
Movie List fix
scrobble redone - for servers far, far away.
AudioAndSubs - with MyPlex/remote server support, though it seems somewhat hit&miss...
poke MyPlex PMS before registering. add 'scheme' to PlexAPI. use 'baseURL' instead of 'PMSaddress' (PlexAPI, PlayVideo - todo: XMLConverter cleanup)
merge salbahra's updates to Trailers (pull req #173) - now working directly from youtube. Thanks!
big changes - small testing: remove ADDR_PMS, remove setting PMS_uuid

- replace ADDR_PMS by PMS_BaseURL. Should fix https:// issue, pull req
#177
- remove PMS_uuid from ATVSettings. Wasn't used for  some time now.
allow aTV to request from multiple PMSs: /PMS(//<type>) - recombine MyPlex into Library.xml - enable search on shared servers
fix: supress "headline" if Library/MyPlex has only one server to show
remove setting "viewmetadata" - split "Movie_List": new movieview option "List With Details"