Remove shadowing by making use of more explicit names

[cjoach]

The name bitResolution is used in different contexts in the library and sometimes the local name shadows the class attribute. This PR modifies the names to be more explicit and remove the -Wshadow warnings.

[RobTillaart]

@cjoach
Which platform/ compiler gives these warning?

[milesburton]

Hmm interesting PR @cjoach. Looks like a decent change. Any issues @RobTillaart ?

[RobTillaart]

@milesburton
I checked the code and there are still a handful occurrences of bitResolution.
However these are all parameters of functions and could be either device- or globalBitResolution.
So they are all renamed consistently ==> no problemo with this PR.
LGTM.

[milesburton]

As always. thanks @RobTillaart . Again thanks for your contribution @cjoach