Comments and minor cleanup for DDG::Goodie::ABC.
Improved readability a bit for DDG::Goodie::ABC.  Added more tests.
Improved comments in DDG::Goodie::ABC.  Added a complimentary test.
Add pick as a trigger word for DDG::Goodie::ABC. +tests.
Added 'select' as a trigger word.  +refactor, +tests
Very minor updates to comments in DDG::Goodie::ABC
Added a test which fails atm for DDG::Goodie::ABC.
Handle queries like 'choose pick or axe'
DDG::Goodie::ABC - Removed @TRIGGERS var and added an attribution.
SumOfNaturalNumbers: Simplify the triggering.
SumOfNaturalNumbers: Faster computation.

- Don't use List::Util for computing the number.
- Stricter regexp.
- Add attribution.
SumOfNaturalNumbers: Add a "from" in the regexp.

So that it can accept "add from 1 to 100"
SumOfNaturalNumbers: Change colon to "is".
PrimeFactors: Remove Wikipedia link.
t/PrimeFactors.t: Update tests.
PrimeFactors: Change colon to 'is'.
PrimeFactors: Change the wording of the result.

- If there are more than one factors say, "The prime factors of __ are __."
- If there is only one factor say, "The number __ is a prime."
PrimeFactor: 0 and 1 are not primes :smile:
Bash: Change style of the IA.

- Put query in the header.
- Change <code> to <pre>
- Add CSS file to change the look of the <pre> tag.
Bash: Update tests.