Use libtinfo as a fallback for curses

This will be done before running the FindCurses cmake module
Configure travis to perform a 32-bit build

- Build targeting 32-bit with travis
- Code in `before_install`/`after_success` was moved to travis.sh since it
  provides greater flexibility for detecting the build matrix environment. This
  improves the build speed since we now install only what's necessary.
- Now clint has a dedicated travis worker
Fix clint.sh wrapper script and broken files

- Fixed clint.sh, it no longer ignores errors in individual files.
- Fixed two files that weren't passing the clint test
Use portable format specifiers: Case %lld - plain - sprintf.

Fix uses of plain "%lld" within sprintf():
- Replace "%lld" with "%" PRId64.
- Cast corresponding argument to (int64_t).
Use portable format specifiers: Case %lld - localized - sprintf.

Fix uses of localized "%lld" within sprintf():
- Replace _("%lld") with _("%" PRId64).
- Cast corresponding argument to (int64_t).
- In *.po files, replace "%lld" with "%<PRId64>".
Use portable format specifiers: Remove branching with LONG_LONG_OFF_T.

After previous commits, branching code by using macro LONG_LONG_OFF_T
becomes unneccesary. Remove it.
Use portable format specifiers: Case %ld - plain - sprintf.

Fix uses of plain "%ld" within sprintf():
- Replace "%ld" with "%" PRId64.
- Cast corresponding argument to (int64_t).
Use portable format specifiers: Case %ld - localized - sprintf.

Fix uses of localized "%ld" within sprintf():
- Replace "%ld" with "%" PRId64.
- Cast corresponding argument to (int64_t).
Use portable format specifiers: Case %ld - plain - fprintf.

Fix uses of plain "%ld" within fprintf():
- Replace "%ld" with "%" PRId64.
- Cast corresponding argument to (int64_t).
Use portable format specifiers: Case %ld - plain - smsg.

Fix uses of plain "%ld" within smsg():
- Replace "%ld" with "%" PRId64.
- Cast corresponding argument to (int64_t).
Use portable format specifiers: Case %ld - localized - smsg.

Fix uses of localized "%ld" within smsg():
- Replace "%ld" with "%" PRId64.
- Cast corresponding argument to (int64_t).
Use portable format specifiers: Case %ld - plain - vim_snprintf.

Fix uses of plain "%ld" within vim_snprintf():
- Replace "%ld" with "%" PRId64.
- Cast corresponding argument to (int64_t).
Use portable format specifiers: Case %ld - localized - vim_snprintf.

Fix uses of localized "%ld" within vim_snprintf():
- Replace "%ld" with "%" PRId64.
- Cast corresponding argument to (int64_t).
Use portable format specifiers: Case %ld - localized - vim_snprintf_add.

Fix uses of localized "%ld" within vim_snprintf_add():
- Replace "%ld" with "%" PRId64.
- Cast corresponding argument to (int64_t).
Use portable format specifiers: Adapt EMSGN/emsgn to use (int64_t).
Use portable format specifiers: Case %ld - plain - EMSGN.

Fix uses of plain "%ld" within EMSGN():
- Replace "%ld" with "%" PRId64.
- No argument cast needed. EMSGN() will take care of that.
Use portable format specifiers: Case %ld - localized - EMSGN.

Fix uses of localized "%ld" within EMSGN():
- Replace "%ld" with "%" PRId64.
- No argument cast needed. EMSGN() will take care of that.
Use portable format specifiers: Case %ld - localized - N_.

Fix uses of plain "%ld" within N_():
- Replace "%ld" with "%" PRId64.
Use portable format specifiers: Case %ld - *.po files.

Fix uses of plain "%ld" within *.po files:
- Replace "%ld" with "%<PRId64>".
Use portable format specifiers: Support 'll' in vim_snprintf.

Add support for 'll' length specifier in vim_snprintf/vim_vsnprintf.