First commit
Added everything to git
Normalized Makefile
Added vertical spacing before (sub)sections

* three blank lines before sections
* two blank lines before subsections
Fixed physical unit conventions

Space character between number and physical unit.
Removed unnecessary indents
Increased verbosity of the "Units" section
Increased verbosity of the "Functions" sections
Rewrote definition of derivatives
Rewrote explanation on second derivatives
Added subsection on formal derivation
Rewrote subsection on derivation rules
Fixed a figure in section on gravity turns
Fixed links in bibliography
Externalizing figures
Added target for PDF optimization in Makefile