MATH 239: added some defns that weren't formally defined(?).
MATH 239: reorganized some defns, added girth definition.
MATH 239: minor wording fixes.
MATH 239: made first planar graph example slightly nicer looking. (#9)
MATH 239: Fixes various spelling and factual errors in many sections.
Merge pull request #21 from jasonchutko/master

Various Fixes
MATH 239: trivial single-word/formatting changes.
Merge branch 'master' of github.com:christhomson/lecture-notes

Conflicts:
	math239.pdf
MATH 239: no longer claiming example 7.19 is not a Hamiltonian cycle.
MATH 239: spelling of colo(u)r is now more Canadian.
MATH 239: added maximum/maximal matching definitions.
MATH 239: a few more minor rewordings.
MATH 239: miscellaneous fixes for the enumeration portion of the course.
MATH 239: updated Hamiltonian theorem name.
MATH 239: added curly braces around a set of size 1.
MATH 239: fixed small typo in Euler's formula proof.
MATH 239: re-alignment of a line in an align* environment.
MATH 239: fixed dual graph drawing + added infinite face to an example.
CS 240/241, MATH 239, and PSYCH 207: typo corrections.
CS 241: trivial wording changes in section 1.