Adds support for SHELL_PIPE Environment Variable.

The isPiped() method now looks for the SHELL_PIPE environment variable.
If found it returns true/false based on the value of SHELL_PIPE. If the
variable is absent existing behaviour to detect a tty remains.

Valid values are boolean strings like 1, 0, yes, no, etc.

To make the CLI ignore that the current TTY is a PIPE and thus enable
ASCII formatting use, SHELL_PIPE=0.
An encoding-safe way of getting string length.

Introduces tests to the project.
Prefix autoloader just to be safe
Merge pull request #53 from wp-cli/fix-53

Fix table padding for accented characters
Hook up Travis-CI
Travis badgelet
Update Composer.json
Abstract and use a common safe str_pad()
Fix copy pasta
Merge pull request #56 from wp-cli/safe-str-pad

Encoding-safe string padding
Added PHP 5.4, 5.6 and HHVM to travis.yml
Merge pull request #58 from Nyholm/patch-1

Added PHP 5.4, 5.6 and HHVM to travis.yml
Constrain width of column headers based on terminal size

Imperfect algo to start
First pass at an algorithm to constrain row values based on width
Update algo to split remaining extra width amongst the large ones
Make padding a class-level variable
Constraint algo needs to accommodate character widths
Merge pull request #50 from dsawardekar/master

Adds support for SHELL_PIPE Environment Variable
Introduce `getDisplayLines()` which will be useful for testing
Ability to set constraint width on renderer