This replaces a segfault when a file can't be found with an exception.
Not as helpful as it could be yet, but certainly better than just
crashing.
Also, make InputFileStream constructor from path "explicit" to avoid
mistakes.
Mostly signed/unsigned comparisons and reordered member
initializations; also a few unused variables.
There are more, but if I chip away at them for a while, who knows, it
may catch on and warnings may eventually become socially stigmatizing.
:)
This is one of those little chores in managing a long-lived C++
project: standard C headers like stdio.h and math.h now have their own
place in the C++ standard as resp. cstdio, cmath, and so on. In this
branch the #include names are updated for the phrase-extract/
subdirectory; more branches to follow.
C++11 adds cstdint, but to support compilation with the previous
standard, that change is left for later.
