allow to use replaceVarsF for plain substitutions
avoid variable clashes when computing overlap
further simplify propositional CASL formulas
attempt to detect incomplete patterns due to conditions
factor out function to quantify over free variables (also for CCC)
do not create wrong sentences in error cases
Merge pull request #1353 from 0robustus1/master

fix argument escaping for wget-Headers
collect exhaustiveness conditions
output readable diagnostics
do not spoil conservativity by proof obligation for definitionality
minor refactorings
refactored sameOpsApp
also properly group domain defs on op symbols
for #1343 all variables need to be considered to avoid clashes
refactored computing formula parts
moved some code and refactored substitution in termination proof
use sameOpSymbs instead of equality, too
added timout to termination prover
only do the necessary work
also collect definedness conditions for casts in substitutions