Fix some typos in lecture 4
Updates for questions on lecture
Merge pull request #18 from mdimitrova/04-fix-typos
Add lecture 05
lecture 05: fix typos
lecture 05: content fixes
Merge pull request #19 from tochev/lecture_05_fixes

Lecture 05 fixes
lecture 06: data transformations
lecture 06: fix typos
Merge pull request #20 from tochev/lecture_06_fixes

lecture 06: fix typos
lecture 07: numbers & transients
Add an example clarifying if-let

The slide did not point out what the if-let semantics are.
Fix typo
Fix several typos and improve formatting
Add more advanced destructuring slides

Rounded out the destructuring slides with:
* :strs and :syms
* destructuring rest sequences as map key/value pairs
* keyword arguments
lecture 04: cleanup and improvements
lecture 08: platforms
Add lecture 09: namespaces, vars and metadata
Remove not existing form, add get to vectors
lecture 01: improve special forms slide