More Chrome tests

Looks like we have an issue as the tests do not pass on most
not-so-old perls. 5.18 is ok.
Chrome: workaround perl < 5.16 bug (inlining+overloading)

Old perls (< 5.16) had an issue in constant inlining combined to
overloading of mathematical operators. The result is that Red+Bold
was inlined into a random number.
The workaround is to not use constant.pm in < 5.16 case, and instead
use closures that will not be inlined.
31-chrome.t: more tests
Travis-CI: shows versions of the shells installed
Chrome: minor optimization

Do not use map() for a 2 elements list.
Travis-CI: revert

Do not try to use shells that we are not using yet in the testsuite.
Travis-CI: run testsuite before compiling (build.pl)

build.pl currently needs 5.10, but it is useful to run the testsuite
also on perl < 5.10, even if build.pl fails. So we run the testsuite
before build.pl.
Compiler/expand: expand inside ARRAY too
mksh: minor optimization in ps1_invisible
Compiler: try to workaround an issue with perl 5.10-5.14
Compiler/reduce: add missing loop label
Compiler: fix previous commit
Double --test now prints the finalized output
Add examples/EnvPS1.PS1

A prompt definition that uses a Perl module from CPAN, Env::PS1,
to show that angel-PS1 can be used as a wrapper around any other Perl
prompt engine.
31-chrome.t: more Chrome tests
Bump $VERSION to 0.92
Release v0.92