Clean and fast readtable implementation
Implement additional IO features

Change some keyword argument names
Allow user to select whether to ignore whitespace padding
Allow user to decide whether to convert strings to factors
Read in column names correctly
Allow user to skip lines at the start of a file
Restore printtable and writetable
Fix test that broke with Julia changes
Fix small bugs re. naming and EOF
Bug fixes

Deal with missing EOL's at the end of data files
Encode completely blank string fields as NA's
Provide more diagnostic information when data can't be read
Deprecate *_table for *table
Merge pull request #287 from HarlanH/readtable

Clean and fast `readtable` implementation