Eina: sanitize eina_path output on Windows
Summary:
* remove additional \ character
* use only / as path separator
Test Plan:
compilation and run
test program :
```
{
elm_app_bin_dir_get();
printf("%s\n", eina_vpath_resolve("(:tmp:)/foo"));
printf("%s\n", eina_vpath_resolve("(:home:)/foo"));
printf("%s\n", eina_vpath_resolve("(:usr.desktop:)/foo"));
printf("%s\n", eina_vpath_resolve("(:usr.documents:)/foo"));
printf("%s\n", eina_vpath_resolve("(:usr.downloads:)/foo"));
printf("%s\n", eina_vpath_resolve("(:usr.music:)/foo"));
printf("%s\n", eina_vpath_resolve("(:usr.pictures:)/foo"));
printf("%s\n", eina_vpath_resolve("(:usr.public:)/foo"));
printf("%s\n", eina_vpath_resolve("(:usr.templates:)/foo"));
printf("%s\n", eina_vpath_resolve("(:usr.videos:)/foo"));
printf("%s\n", eina_vpath_resolve("(:usr.data:)/foo"));
printf("%s\n", eina_vpath_resolve("(:usr.config:)/foo"));
printf("%s\n", eina_vpath_resolve("(:usr.cache:)/foo"));
printf("%s\n", eina_vpath_resolve("(:usr.run:)/foo"));
printf("%s\n", eina_vpath_resolve("(:usr.tmp:)/foo"));
printf("%s\n", eina_vpath_resolve("(:app.dir:)/foo"));
printf("%s\n", eina_vpath_resolve("(:app.bin:)/foo"));
printf("%s\n", eina_vpath_resolve("(:app.lib:)/foo"));
printf("%s\n", eina_vpath_resolve("(:app.data:)/foo"));
printf("%s\n", eina_vpath_resolve("(:app.locale:)/foo"));
printf("%s\n", eina_vpath_resolve("(:app.config:)/foo"));
printf("%s\n", eina_vpath_resolve("(:app.local:)/foo"));
printf("%s\n", eina_vpath_resolve("(:app.tmp:)/foo"));
}
```
before patch :
```
C:\Documents\msys2\tmp/foo
C:\Users\vincent.torri/foo
C:\Users\vincent.torri\Desktop/foo
C:\Users\vincent.torri\Documents/foo
C:\Users\vincent.torri\Downloads/foo
C:\Users\vincent.torri\Music/foo
C:\Users\vincent.torri\Pictures/foo
C:\Users\Public\/foo
C:\Users\vincent.torri\AppData\Roaming\Microsoft\Windows\Templates/foo
C:\Users\vincent.torri\Videos/foo
C:\Users\vincent.torri\AppData\Local\/foo
C:\Users\vincent.torri\AppData\Roaming\/foo
C:\Users\vincent.torri\AppData\Local\/foo
C:\Users\vincent.torri\AppData\Roaming/foo
C:\Users\vincent.torri\AppData\Local\Temp/foo
C:/Documents/msys2/opt/entice_64/bin/foo
C:/Documents/msys2/opt/entice_64/bin/foo
C:/Documents/msys2/opt/entice_64/lib/foo
C:/Documents/msys2/opt/entice_64/share/foo
C:/Documents/msys2/opt/entice_64/share/foo
C:\Users\vincent.torri\AppData\Roaming\/entice/foo
C:\Users\vincent.torri\AppData\Local\/entice/foo
C:\Users\vincent.torri\AppData\Local\Temp/entice/foo
```
after patch
```
C:/Documents/msys2/tmp/foo
C:/Users/vincent.torri/foo
C:/Users/vincent.torri/Desktop/foo
C:/Users/vincent.torri/Documents/foo
C:/Users/vincent.torri/Downloads/foo
C:/Users/vincent.torri/Music/foo
C:/Users/vincent.torri/Pictures/foo
C:/Users/Public/foo
C:/Users/vincent.torri/AppData/Roaming/Microsoft/Windows/Templates/foo
C:/Users/vincent.torri/Videos/foo
C:/Users/vincent.torri/AppData/Local/foo
C:/Users/vincent.torri/AppData/Roaming/foo
C:/Users/vincent.torri/AppData/Local/foo
C:/Users/vincent.torri/AppData/Roaming/foo
C:/Users/vincent.torri/AppData/Local/Temp/foo
C:/Documents/msys2/opt/entice_64/bin/foo
C:/Documents/msys2/opt/entice_64/bin/foo
C:/Documents/msys2/opt/entice_64/lib/foo
C:/Documents/msys2/opt/entice_64/share/foo
C:/Documents/msys2/opt/entice_64/share/foo
C:/Users/vincent.torri/AppData/Roaming/entice/foo
C:/Users/vincent.torri/AppData/Local/entice/foo
C:/Users/vincent.torri/AppData/Local/Temp/entice/foo
```
Reviewers: raster
Reviewed By: raster
Subscribers: cedric, #reviewers, #committers
Tags: #efl
Differential Revision: https://phab.enlightenment.org/D12306