Merge pull request #8 from pulpillo/master

Merge first week challenge of pulpillo
First round for P01 to P10. Some TODOs and improvements are pending
Merge branch 'master' of github.com:scala-developers-bcn/challenges
first 10 problems solved, pending sbt config
files for this week in scala bcn dev assignment
Merge pull request #11 from robertrv/master

solutions for the first 10 problems
Merge pull request #9 from pulpillo/master

Added sbt file
Merge pull request #10 from padilo/master

First 10 problems, pending sbt config
ignore IDEA control files
Solved P11
reviewed isPalindrome. It now reuses reverse. I actually copied this solution from other users.
solved P12
Fixed last() and penultimate() to support empty list or shourt lists ;-)
Solved P13
Solved P14
Added comment on a possible improvement
solved P15. Also removed usage of flatten, replaced with flatMap(identity)
Solved P16
Solved P17
Merge pull request #12 from ignasi35/master

Solved P11 to P17