Fix text objects when :set keymodel+=stopsel.

With that setting (which is set by :behave mswin), movement of cursor keys stops the visual selection, but the text objects are based on that. Replace the use of <Left> / <Right> with the canonical h / l; those are not affected by this setting.
Merge pull request #27 from inkarkat/fix-keymodel-stopsel

Fix text objects when :set keymodel+=stopsel.
added /doc/tags to gitignore
describing slow plugin
remove leading slash
output amount of different items
analyze: prevent error for empty attributes
:Analyze: highlight 1 line as title
updated doc
allow to left-arrange columns when using :ArrangeCol
updated documentation
SumCol did not detect negative values
correctly set b:did_ftplugin
make column mode work better
updated documentation
fix some typos in the documentation
This is release 0.30
break endless loop when using H on first cell (fixes #31)
AddColumn <nr> throwed error (fixes #32)
Check for existence of header field, before trying to access it