Add DCSBIOS_ADD_EXPORT_TARGET and DCSBIOS_REMOVE_EXPORT_TARGET commands

Refs #6
Update userguide.adoc
Update userguide.adoc

updated to line 110.
Updated to line 156
Update userguide.adoc

edits to line 164
Update userguide.adoc
move documentation to DCS-BIOS\Scripts\doc
reformat userguide.adoc to use one line per sentence
add TCP support