Fix grammar and spelling in comments and text

camlibs/canon/TODO

@@ -19,7 +19,7 @@ List of work that still has to be done on this driver:
  - handle rotated images correctly (how?)
 
  - A5 support is completely broken, with the new filename based API, the 
-   directory caching mecanism must be completely revisited. On the
+   directory caching mechanism must be completely revisited. On the
    other hand, when removing the internal caching layer, we perhaps
    facilitated the solution to this problem.
 

camlibs/canon/canon.c

@@ -12,7 +12,7 @@
  * use a FireWire (IEEE 1394) interface.
  *
  * We are working at moving serial and USB specific stuff to serial.c
- * and usb.c, keeping the common protocols/busses support in this
+ * and usb.c, keeping the common protocols/buses support in this
  * file.
  */
 #define _DEFAULT_SOURCE

camlibs/canon/serial.c

@@ -211,7 +211,7 @@ canon_serial_send (Camera *camera, const unsigned char *buf, int len, int sleep)
  * @gdev: serial port to use
  * @to:   timeout in milliseconds
  *
- * Sets the timeout, in miliseconds.
+ * Sets the timeout, in milliseconds.
  *
  */
 static void