Ran ispell on Task_Parallelism_and_Synchronization.tex
Preliminary version of special functions proposal.
First update.
Make narrowWideReferences its own pass.
Dereference widenMap at the call site.
Update compilerPerformance.perfkeys with new pass.
io: add function isDir

This function will check whether the given path is a directory.
io: add isFile

This function will check whether the given path is a regular file.
Fix list_view() and aid() debugging tools.
add error checking on number of captures
add error checking on overflow in allocation for MAYBE_STACK_ALLOC
enable env CHPL_FAST_FLAG as alternative to --fast
support octal in writef/readf
 fix unused variable
 add octal tests
include octal as base specifier
Octal print test now passes
Merge branch 'master' into specAddSpecialFunctions
Distinguish C string utilities that return allocated strings from those that don't.

Some utilities that return a c_string return a string that has been freshly allocated off
the heap, while others to not.  To make the interface self-documenting, I created yet
another alias for "const char*" and called it c_string_copy.  To that one, I ascribed the
interpretation that it contains a freshly-allocated C string.  Thus:
```
  c_string foo();
    // Returns a pointer-copy of (i.e. a reference to) a C string owned by another program
    // entity.  The caller of foo() should not free the return value.
  c_string_copy bar();
    // Returns a freshly-allocated C string.  The caller should free the returned C string
    // (or arrange in some other way that it be cleaned up).
```
Since the C compiler treats the type aliases `c_string` and `c_string_copy` as equivalent,
a variable (or return value) of type `c_string_copy` can be supplied to a routine
expecting a `c_string` argument.

### DETAILS
####./runtime/include/chpl-mem.h
Piped the filename and linenumber arguments through, for better memory tracking.

####./runtime/include/chpl-string-support.h
Added the new typedef `c_string_copy` with comments explaining how it differs from c_string.
Updated return value types using `c_string_copy` where the returned string is
heap-allocated and should be managed by the caller.

####./runtime/include/chpl-string.h
Added comments to describe the interface to stringMove().
Updated the return type of remoteStringCopy, to say that it returns a heap-allocated c_string.

####./runtime/include/chplcast.{h,c}
Updated the interfaces to all integral_to_c_string() functions, to say that they return a
heap-allocated c_string result.
Added a comment to warn that this is not true for the boolean_to_c_string() functions.
Added comments to chpl_string_to_c_string and c_string_to_chpl_string, explaining why they
do not leak memory.

####./runtime/include/chplgmp.{h,c}
Changed the return type of chpl_gmp_mpz_get_str() to say that it returns a heap-allocated
c_string.

####./runtime/include/chplsys.{h,c}
Changed the return type of chpl_nodeName() to say that it returns a heap-allocated
c_string.

####./runtime/include/qio/qio_formatted.{h,c}
Changed the return type of qio_encode_to_string() to say that it returns a heap-allocated
c_string.

####./runtime/src/chpl-string-support.c
Changed the return type of chpl_format(), string_copy(), string_concat(), string_select()
and string_index() to say that they return a heap-allocated c_string.
Updated string_index to ensure that the returned c_string_copy can always be safely
deallocated.

####./runtime/src/chpl-string.c
Added comments about the semantics of stringMove().
Changed the return type of remoteStringCopy() to say that it returns a heap-allocated
c_string.

####./runtime/src/config.c
Added a comment about chpl_config_get_value() being inherently thread-safe.
Merge remote-tracking branch 'upstream/master' into env-for-fast-2