Introduce html.h

All html-functions can be quite easily separated from the rest of cgit, so
lets do it; the only issue was html_filemode which uses some git-defined
macros so the function is moved into ui-shared.c::cgit_print_filemode().

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

html.h

@@ -0,0 +1,18 @@
+#ifndef HTML_H
+#define HTML_H
+
+extern int htmlfd;
+
+extern void html(const char *txt);
+extern void htmlf(const char *format,...);
+extern void html_txt(char *txt);
+extern void html_ntxt(int len, char *txt);
+extern void html_attr(char *txt);
+extern void html_hidden(char *name, char *value);
+extern void html_option(char *value, char *text, char *selected_value);
+extern void html_link_open(char *url, char *title, char *class);
+extern void html_link_close(void);
+extern void html_fileperm(unsigned short mode);
+extern int html_include(const char *filename);
+
+#endif /* HTML_H */