travis: Use "exit 1" in case of linter failure (#62)

* travis: Use "exit 1" in case of linter failure

* Fix double spacing

.travis.yml

@@ -10,8 +10,8 @@ install:
   - pip3 install --user codespell
 
 script:
-  - git grep $'\r' -- "*.asciidoc" "*.md" && echo "^ Possible Windows style line ending detected. Please use Unix style line endings (\n)." && false || true
-  - git grep ' $' -- "*.asciidoc" "*.md" && echo "^ Trailing space detected at end of line. Please remove." && false || true
-  - git grep $'\t' -- "*.asciidoc" "*.md" && echo "^ Use of tabs detected. Please use space for indentation." && false || true
-  - git grep "[^ ]  [^ ]" -- "*.asciidoc" "*.md" && echo "^ Satoshi style double spacing detected. Sorry Satoshi, please use single spacing." && false || true
+  - git grep $'\r' -- "*.asciidoc" "*.md" && echo "^ Possible Windows style line ending detected. Please use Unix style line endings (\n)." && exit 1 || true
+  - git grep ' $' -- "*.asciidoc" "*.md" && echo "^ Trailing space detected at end of line. Please remove." && exit 1 || true
+  - git grep $'\t' -- "*.asciidoc" "*.md" && echo "^ Use of tabs detected. Please use space for indentation." && exit 1 || true
+  - git grep "[^ ]  [^ ]" -- "*.asciidoc" "*.md" && echo "^ Satoshi style double spacing detected. Sorry Satoshi, please use single spacing." && exit 1 || true
   - codespell --ignore-words-list=que $(git ls-files -- "*.asciidoc" "*.md")

ch01.asciidoc

@@ -132,7 +132,7 @@ A person or platform offering content on the web.
 They want to install a pay wall or get tipped by their fans and consumers.
 This could even include music or video streaming on demand paying in real time.
 
-John is a 9 year old boy from Australia, who wanted a games console just like his friends. However he was told by his dad that in order to buy it, he had to earn the money by himself. Now John is an aspiring artist so he knows that while he is still learning, he can't charge much for his artwork.  After learning about Bitcoin, he managed to setup a website to sell his drawings across the internet. By using the Lightning Network, John was able to charge as little as $1 for one of his drawings.  By being able to set a fair price, which would normally be considered a micropayment and as such not possible with other payment methods, and by using a global currency such as Bitcoin, John was able to sell his art work to customers all over the world and in the end buy the games console he so very much wanted.
+John is a 9 year old boy from Australia, who wanted a games console just like his friends. However he was told by his dad that in order to buy it, he had to earn the money by himself. Now John is an aspiring artist so he knows that while he is still learning, he can't charge much for his artwork. After learning about Bitcoin, he managed to setup a website to sell his drawings across the internet. By using the Lightning Network, John was able to charge as little as $1 for one of his drawings. By being able to set a fair price, which would normally be considered a micropayment and as such not possible with other payment methods, and by using a global currency such as Bitcoin, John was able to sell his art work to customers all over the world and in the end buy the games console he so very much wanted.
 
 gamer::
 Similar to the content creator, a gamer and live streamer would like to be tipped.