Update Travis settings

[fingolfin]

Test against GAP master branch, as well as versions 4.9, 4.10 and 4.11. Don't bother to test with different C compilers, or in 32 bit mode.

[fingolfin]

Oops, actually 4.11 was missing, just updated the PR to correct that.

Note that all Travis tests are currently failing -- I can push a commit to this PR which also corrects that, I guess.

[fingolfin]

Specifically, the tests report this (and I wonder if this hints at a genuine bug / regression):

########> Diff in /Users/mhorn/Projekte/GAP/repos/pkg/qpa/pkg/pkg/tst/testall.tst:708
# Input is:
TiltingModule(P,1);
# Expected output:
[ 0, [ 0 -> 0:(1,4,3) -> -1:(1,4,3) -> 0, 0 -> 0:(0,2,2) -> -1:(0,2,2) -> 0,
      0 -> 0:(1,2,2) -> -1:(1,2,2) -> 0 ] ]
# But found:
[ 0, [ true, true, true ] ]
########

[codecov[bot]]

Codecov Report

Merging #37 into master will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #37   +/-   ##
=======================================
  Coverage   59.87%   59.87%           
=======================================
  Files          70       70           
  Lines       20380    20380           
=======================================
  Hits        12203    12203           
  Misses       8177     8177

[fingolfin]

@sunnyquiver thanks for fixing the tests. I've now rebased all my PRs