updated README. Be clear about RFCs supported/not
complete EOR support, simple reordering of methods
add previously untracked tulip files
bring README in line with implementation

begin describing SYNCH, not all statements are yet true ..
all around improvements and refactoring

and docfixes. better CR handling for ``line_received`` callback,
de-coupling from ``data_received``. finer line flow control handling.
implemented LNEXT (^V) to insert raw characters. better bell() handling
fixed SLC_EW (erase word)