[doc] Updated web services documentation with info about new methods.
[doc] Updated web services documentation with info about new methods.

FEA: ItEr75S12AllowExportOneEntity

LibrePlan/libreplan,LibrePlan/libreplan,LibrePlan/libreplan,skylow95/libreplan,poum/libreplan,PaulLuchyn/libreplan,Marine-22/libre,skylow95/libreplan,poum/libreplan,dgray16/libreplan,PaulLuchyn/libreplan,skylow95/libreplan,Marine-22/libre,PaulLuchyn/libreplan,dgray16/libreplan,dgray16/libreplan,skylow95/libreplan,skylow95/libreplan,PaulLuchyn/libreplan,dgray16/libreplan,LibrePlan/libreplan,poum/libreplan,poum/libreplan,LibrePlan/libreplan,poum/libreplan,PaulLuchyn/libreplan,skylow95/libreplan,dgray16/libreplan,Marine-22/libre,PaulLuchyn/libreplan,Marine-22/libre,PaulLuchyn/libreplan,Marine-22/libre,LibrePlan/libreplan,poum/libreplan,Marine-22/libre,dgray16/libreplan,LibrePlan/libreplan,dgray16/libreplan