Fix typo on Getting Started guide (4.3)

circunstances -> circumstances
Merge pull request #111 from gmcabrita/patch-1

Fix typo on Getting Started guide (4.3)
Fix Crashcourse section First-Class functions when using named function
Merge pull request #112 from edgurgel/patch-1

Fix Crashcourse section First-Class functions when using named function
More info on sharing tasks
Fix headers on Mix chapter 3 guide
Update master docs
Update precompiled package notes
Mention MinGW and remove Windows notice
Include a link to the PeepCode Meet Elixir video with Jose Valim.
Use proper E for Jose's name.
Merge pull request #113 from topfunky/peepcode-elixir

Include a link to the PeepCode Meet Elixir video with Jose Valim.
Add some marging in between learning resources
Do not mention BEAM tasks
First-Class functions examples need to be more specific