* make MatrixError implement error interface

* let ParseTSParam return error when no int transmitted

* fix to high cyclo for SendEvent

* Move generateSendEvent below SendEvent

* Drop ParseIntParam() as it is used only in one place

* Parse ts param at the beginning of JoinRoom

to be able to abort right in the beginning and
to not parse the MatrixError to get an error response

* make ParseTSParam() return error instead of JSONResponse