Correct GitHub Syntax Highlighting in API markdown file

Check whether an axis has a generator, rather than a mode. In most cases
this is functionally the same, but it also handles the case where an
axis mode plug-in specifies only the formatter, and expects to use the
default base-10 generator.

Added an option to control legend sort order.

Added a legend 'sorted' option that allows sorting of legend entries
independent of series order.  It accepts either null/false, true,
'ascending', 'descending' or a comparator function.

Throw error when flot.time plugin is missing.

- The faster toFixed alternative now returns a string, as tickFormatter
is expected to do

We changed the === to == and removed the typeof operator.  We also changed the tabs to spaces.

Switched to a much a faster default tickFormatter.

Fixes issues 709 on google code.

- toFixed() is sloooow
http://jsperf.com/tofixed-vs-factor

Better date/time formatting

Fix minTickSize for year units

Timezone support, time mode pluginification

time zones.

Added a 'right' option for bar alignment.

Convert README to markdown format