Remove ptr typedefs

[Anilm3]

For convenience and reducing characters, I introduced a ptr typedef (using declaration) on certain classes which were typically used as a shared_ptr. Over time the use of this ptr typedef was extended to other classes, some as shared_ptr and some as unique_ptr, which has made it very difficult to understand the underlying pointer type. This PR removes them to make the underlying pointer type more explicit.

[codecov-commenter]

Codecov Report

Merging #212 (cbe4028) into master (f0a48e4) will not change coverage.
The diff coverage is 96.00%.

@@           Coverage Diff           @@
##           master     #212   +/-   ##
=======================================
  Coverage   82.58%   82.58%           
=======================================
  Files         105      105           
  Lines        3986     3986           
  Branches     1813     1813           
=======================================
  Hits         3292     3292           
  Misses        281      281           
  Partials      413      413           

Flag	Coverage Δ
waf_test_none	82.47% <96.00%> (ø)
waf_test_sse2	82.55% <96.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
src/collection.cpp	81.81% <ø> (ø)
src/collection.hpp	80.00% <0.00%> (ø)
src/exclusion/input_filter.hpp	100.00% <ø> (ø)
src/exclusion/rule_filter.hpp	100.00% <ø> (ø)
src/generator/base.hpp	100.00% <ø> (ø)
src/matcher/base.hpp	87.50% <ø> (ø)
src/parser/specification.hpp	100.00% <ø> (ø)
src/rule.cpp	100.00% <ø> (ø)
src/rule.hpp	84.00% <ø> (ø)
src/ruleset_builder.cpp	81.65% <ø> (ø)
... and 12 more

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[cataphract]

if you wanted to save typing, you could use typedefs like uptr and sptr, but this is fine too