(PUP-2654) Capitalize each segment of a resource type "label"

When a Resource type is stringified it selects the short notation
(e.g. Fee::Foo) over the longer (e.g. Resource[Fee::Foo]), and
when doing so it should output each segment of the FQN with a
capital letter. The current implementation only capitalizes
the initial letter (e.g. Fee::foo::fum).

This fixes the implementation of
TypeCalculator.string_PResourceExpression to capitalize all segments.
Here is another interesting benchmark. It appears that constructing a string using concatenation an constants is faster than interpolation.

````ruby
require 'benchmark'

FORMAT = "%s[%s]"
OPEN = "["
CLOSE = "]"

iterations = 10_000_000
first = "hi"
second = "there"
Benchmark.bm(24) do |x|
  x.report("interpolation") { iterations.times { "#{first}[#{second}]" } }
  x.report("concatenation") { iterations.times { first + "[" + second + "]" } }
  x.report("join") { iterations.times { [first, "[", second, "]"].join } }
  x.report("sprintf") { iterations.times { sprintf("%s[%s]", first, second) } }

  x.report("concatenation(const)") { iterations.times { first + OPEN + second + CLOSE } }
  x.report("join(const)") { iterations.times { [first, OPEN, second, CLOSE].join } }
  x.report("sprintf(const)") { iterations.times { sprintf(FORMAT, first, second) } }
end
````

````
[12:16:49][Ruby(ruby-1.9.3-p484)][Git(master)] andy:puppet-specifications
> ruby string_construct.rb
                               user     system      total        real
interpolation              4.540000   0.000000   4.540000 (  4.542264)
concatenation              5.280000   0.010000   5.290000 (  5.278948)
join                      10.140000   0.030000  10.170000 ( 10.179316)
sprintf                    9.140000   0.010000   9.150000 (  9.142952)
concatenation(const)       3.470000   0.000000   3.470000 (  3.468593)
join(const)                8.420000   0.080000   8.500000 (  8.506765)
sprintf(const)             9.110000   0.010000   9.120000 (  9.115566)
````