Added the look direction to SAR sensor model (#283)

* Non-compiling rough-draft of groundToImage and helper functions

* Merge with upstream changesa and add compiling version of groundtoimage

* Incremental improvements. Moved secant function back into previous function because two return values

* Compiles and some cleanup

* I might regret this, but pushed dopplerShiftFrequency calculation to a lambda fn and made secantRoot a function

* Clean up and move secantRoot to utilities. Add test. Update brentsMethod to take a lambda and update other code accordingly

* remove ooo

* Move bounds checking into secantRoot function and move exceptions around

* Replace placeholders with member variables.

* Add getRangeCoefficients function

* Update to include wavelength, add tests for functions, and fix broken functions based on tests

* Update g->i test with real line, samp image values and fix accidental copy-paste errors

* Tweaked ground to image

* Updated format and associated parsing of range coefficients and times

* Oops, missed some files last commit

* Add 0.5 offset to line calculation needed and update tests to add an Isis comparison test

* Updated Test SAR ISD

* Removed ISIS test and fixed ISD parsing test failure

* Add look direction to SAR

* Updated sar look direction to use an enum

Co-authored-by: Jesse Mapel <jmapel@usgs.gov>