Merge pull request #24 from esheldon/master

Converted to new style classes and extended calling syntax
Merge pull request #25 from esheldon/master

updating the changelog and some other docs
added new install instructions
added link to new docs
removed old matlab interface example
added link to examples dir to README.md
updated example 7
added data needed for example 7
Update ChangeLog
changed xlog,ylog to use True/False instead of 0 or 1
config parser now reads True/False
changed back xlog/ylog because not consistent with rest of code
fixed bug in DataArc and PlotArc
Update ChangeLog
reworked log plots. Default to symbol.

The default marker is now a symbol.

Factored out the code to deal with log plots and plot ranges.

Allow type= as a shorthand, with the marker type determined by the
value.  The other shorthands are dealt with when the maker is created,
e.g. Points or Curve

Allow scalar input

Documented the changes
document allowing scalars