fix coverity script
der test: also run der_length_utf8_string()
der_decode_sequence_multi: calm coverity
start updating documentation
more documentation
update README
update changes document

[skip ci]
oops, it's not yet released

[skip ci]
update changes document
trim trailing spaces
some minor corrections/improvements
add documentation of the newly added ASN.1 types
add documentation of the new RSA API functions
fix build error
quiet down the output of 'make docs'
use ulong32 resp. ulong64 in the tables of the Macros section

This closes #16
add SHA512/t documentation
added sec 11.3, dynamic lang support
adapt dynamic language documentation to modified API and functionality
update documentation regarding RSA key import/export