ignore .rds generated during pdf builds

modification to .gitignore and experimentation with combined SVN/Git
system
Added event frame support to mleframe

The x argument of mleframe can be a time-event dataframe
Expanded mleframe man page to cover time-event DF

Man page for mleframe expanded to cover multiple use of x argument.
Stability enhancements to mlefit

Added a maximum iteration limit to the simplex optimization routine in
C++ to catch an observed bug.  Added optional control and expanded
output of the optimization through mlefit.
Arguments to the C++ functions have been consolidated in list objects.
A debias argument has been added, but not yet implemented.
Added bias adjustments to mlefit.

implemented the debias argument for mlefit with calls to new rba and
hrbu functions (slight changes from original debias code).  Added
data_types attribute to record number of data points, n, and number of
s/d/i data points.
Merge pull request #1 from Abernethy/dev1

Dev1