Add GPL2 Header.
Initial commit of save.dta13.

save.dta13 allows you to create a version 117 dta-file from a R object of class data.frame. This implementation allows you to create a complete dta-file using all of the (required) version 117  features:
- datalabel
- timestamp
- map (14 byte positions in the dta-file)
- variable types
- varnames
- formats
- value labels
- characteristics
- strL (strings up to 2 billion characters)

Writing files was tested using 64bit Linux on a little endian machine. Additional testing was done using 64bit Windows 7.
rename path argument and tidy up documentation
Merge branch 'testing' into write
fixed wrong function name
update documentation
add write branch
Update README.md
Corrections to strL detection and to logicals.
Indent and move txtlen in loop.
New option add.rownames and documenting missing options.

add.rownames adds rownames as variable to an object. Stata does not know rownames, so we have to add them or lose them.
correction of add.rownames.
add.rownames option to read.dta13. If we wrote it, we should be able to use it.
cleaning
Fixup
Merge branch 'testing' into write

Conflicts:
	NAMESPACE
	R/read.R
	man/read.dta13.Rd
Save strings in WIndows-1252 encoding
Cherry-pick local fixes.
Merge branch 'write' of https://github.com/sjewo/readstata13 into write
Add compression option. If compress=TRUE we try to be smart and store integers as char, byte or int and numerics as floats or double.
Default is FALSE.