removes cyclopts namespace and directory, adjusts symbolic functions accordingly

* flattens cyclopts dir to top level directory in src and tests
* removes cyclopts namespace
* moves limits.h members to cyc_limits.h
* renames Function members in symbolic_functions type files to SymFunctions to fix collision with former Cyclopts::Function members

note that the current dev. HEAD appears to actually pass CI:
http://submit-1.batlab.org/nmi/results/details?runID=187604

as does this PR:
http://submit-1.batlab.org/nmi/results/details?runID=187615