Implemented L10nConvertStr as only char* -> char* (type).

This may be used in other l10n functions, since it was designed to receive void* pointer.
Find sizeof(size_t) is 4 (uint32_t?) in Guided Fate Paradox. Thank @B1ackDaemon for testing.
Changed log content for this function. Also fixed many typos..
Need windows sdk for code page transformation on windows. Need iconv to build on Linux/Mac.
Original source for char to char codepage transformation is already tested using codeblocks and vs.
Noticed l10n_conv_t is omitted in reference, which may be replaced by iconv_t or simply other function.
Modified .travis.yml to apt-get install libc6-dev and removed -liconv from CMakeFile.txt.

.travis.yml

@@ -16,7 +16,7 @@ before_install:
   - echo "yes" | sudo apt-add-repository 'deb http://repos.codelite.org/wx3.0/ubuntu/ precise universe'
   - sudo add-apt-repository ppa:ubuntu-toolchain-r/test -y
   - sudo apt-get update
-  - sudo apt-get install libwxgtk3.0-dev libopenal-dev freeglut3-dev libglew-dev
+  - sudo apt-get install libwxgtk3.0-dev libopenal-dev freeglut3-dev libglew-dev libc6-dev
   - sudo apt-get install aria2 -qq
   - download_extract() { aria2c -x 16 $1 -o $2 && tar -xf $2; }
   - if [ "$CXX" = "g++" ]; then sudo apt-get install -qq g++-4.8; export CXX="g++-4.8" CC="gcc-4.8"; else sudo apt-get install libstdc++-4.8-dev; fi