Removing CentOS 5 and Ubuntu 10.04 from the test matrix

Workshop still works on both CentOS 5 and Ubuntu 10.04, but these
machines are hard to test consistently. Until we pack our own
virtual machines, we'll put them aside.

The test matrix and related documentation was also updated
to reflect those changes.
Adding ignore pattern option for depur coverage

Now depur.sh can receive the --ignore option with a pattern
to ignore files and don't display coverage for them.

This is useful for ignoring coverage of the test files
themselves.

Code formatting was also applied to better comply
to our coding style.
Improvements on posit, fixing timeout command issues, error handling

The posit/cov.sh was changed to pass the pattern for test files
to depur --ignore. This will prevent tests for --report=cov to
display results for the test files themselves.

posit now changes the errexit option (set +e) before running a test,
but it reverts back to whatever the setting was just after running
it. This will prevent some shells from interrupting the execution
of the entire suite.

The timeout command has differences on various platforms. A real
time test to check for the most common versions was added and
it should not break on busybox anymore.

Several instances of unquoted variables and other misc coding
formatting bits were applied.
Error handling on trix tool, formatting

The trix tool now changes and restores the errexit option the
same way posit does. This prevents the matrix from stopping
when a single environment fails.
Better docs for posit, .editorconfig and code formatting

An .editorconfig file is now included with our basic choices
for tabs, newlines and similar editor configuration. Please
refer to the file itself for more information.

Documentation for posit was fixed and slightly improved.

Minor code formatting and style was applied to misc files.