travis: Bump pulp and purs + fix build

I've changed `sudo` config to `required` as it is a solution listed here:

purescript/purescript#1880

Author: paluh

.travis.yml

@@ -1,6 +1,6 @@
 language: node_js
 
-sudo: false
+sudo: required
 
 addons:
   apt:
@@ -16,7 +16,7 @@ addons:
     - latexmk
 
 node_js:
-- '5.5'
+- '7'
 
 env:
   matrix:
@@ -26,10 +26,10 @@ env:
   - secure: "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"
 
 install:
-- wget -O $HOME/purescript.tar.gz https://github.com/purescript/purescript/releases/download/v0.11.3/linux64.tar.gz
+- wget -O $HOME/purescript.tar.gz https://github.com/purescript/purescript/releases/download/v0.11.7/linux64.tar.gz
 - tar -xvf $HOME/purescript.tar.gz -C $HOME/
 - chmod a+x $HOME/purescript
-- npm install -g bower pulp@next
+- npm install -g bower pulp@12.0.1
 - bower install
 - pip install --user -r docs/requirements.txt