Fix 4 typos

I checked the slides and found 4 different small typos.
Merge pull request #27 from yasen23/01-fix-typos

Fix 4 typos
Fix 5 typos
Lecture 04
Fix some typos
Merge pull request #29 from Monika-Ilieva/lecutre-02-conditions-arrays

Fix 5 typos
Fix indentation and typo
Merge pull request #30 from EmanuelaMollova/04-fix-typos

Fix some typos
Merge pull request #31 from NikolayGenov/04-fix-typos

Fix some typos and indentation
Fix 2 typos
Merge pull request #32 from Monika-Ilieva/03-hashes-methods-objects-classes

Fix 2 typos
Replace albino with pygments.rb

Albino seems to be deprecated in favor of pygments.rb. The latter is
also faster than albino–on my machine that's nearly twice as fast.
Lecture 05
Fix small typos
Merge pull request #35 from NikolayGenov/05-fix-typos

Fix small typos
Fix typos and examples in lecture 04
Merge pull request #34 from dkeranov/04-fix-examples

Fix typos and examples in lecture 04