all: move headers to include folder

Signed-off-by: Mahyar Koshkouei <mk@deltabeard.com>

include/file.h

@@ -0,0 +1,26 @@
+enum file_types
+{
+	FILE_TYPE_ERROR = 0,
+	FILE_TYPE_WAV,
+	FILE_TYPE_FLAC,
+	FILE_TYPE_VORBIS,
+	FILE_TYPE_OPUS,
+	FILE_TYPE_MP3,
+	FILE_TYPE_SID
+};
+
+/**
+ * Obtain file type string from file_types enum.
+ *
+ * \param	ft	File type enum.
+ * \return		String representation of enum.
+ */
+const char* fileToStr(enum file_types ft);
+
+/**
+ * Obtains file type.
+ *
+ * \param	file	File location.
+ * \return			file_types enum or 0 on error and errno set.
+ */
+enum file_types getFileType(const char *file);