Builder|Linux: Label stable packages using the build number, too

To enable mixing unstable and stable packages, the build label is
included in both.
Builder: Determine new files based on modification time

Instead of naively looking at files that did not exist before, the
new output file detector now uses modification time as well to
determine if a file is new (and needs to be copied to the master).
Fixed|libdeng2: Compiler warning about truncating a double
libdeng2|VectorN<>: Equality operators for floating-point vector types
Fixed|Deh Reader: Incorrect return value of parseWeaponNum
libdeng2|VectorN<>: Absolute, dot and min/max axis functionality for vectors
Merge branch 'master' of github.com:skyjake/Doomsday-Engine
Fixed|Renderer: Sky fog

Fog was no longer being enabled when rendering the sky sphere/models,
likely due to a refactoring oversight.
Debug|Fixed: inspecttexture failed to output the TextureVariantSpec
Debug|TextureVariantSpec|Fixed: TextureVariantSpec::asText() was missing some info
Debug: More info in TextureVariantSpec::asText()

GL wrap modes and gamma-correction/no-stretch/to-alpha flags.
Merge branch 'master' into ui-framework