Add overlap and align modes to context

Add overlap and align modes to context

Simplify the API by adding overlap and byte alignment modes to the
context. SOEM can then call the correct functions internally. As a
consequence the following functions are removed from the public API:

   ecx_config_overlap_map_group
   ecx_config_map_group_aligned
   ecx_send_overlap_processdata_group
   ecx_send_overlap_processdata

Change-Id: I0404c4fbaa6be68be4c584af0cc9d62e780c7aaa