Fix typos (user facing and non-user facing) (#727)

Found via `codespell v2.1.dev0`  
`codespell -q 3 -S *.po,./lib-src -L parm,parms,toke`

cmake-proxies/CMakeLists.txt

@@ -18,7 +18,7 @@ cmd_option( ${_OPT}lib_preference
 #     symbol   suffix for the "USE_<symbol>" variable that the Audacity
 #              target uses to include/exclude functionality.
 #
-#     requried Determines if the library is required or not.  If it is,
+#     required Determines if the library is required or not.  If it is,
 #              the user is not given the option of enabling/disabling it.
 #
 #     check    Determines if local/system checks should be performed here

cmake-proxies/cmake-modules/AudacityFunctions.cmake

@@ -145,7 +145,7 @@ endfunction()
 # project in Visual Studio. Sweet right? Well, not quite...
 #
 # We want the Audacity target to be the startup project to provide
-# eaiser debugging. But, if we do that, the ALL_BUILD target is no
+# easier debugging. But, if we do that, the ALL_BUILD target is no
 # longer "in control" and any dependents of the Audacity target would
 # not get built. So, targets like "nyquist" and "plug-ins" would have
 # to be manually built. This is not what we want since Nyquist would

cmake-proxies/ffmpeg/CMakeLists.txt

@@ -24,7 +24,7 @@ cmd_option( ${_OPT}use_ffmpeg
             STRINGS "loaded" ${opt} "off"
 )
 
-# Deteremine if it will be turned off, linked to, or loaded
+# Determine if it will be turned off, linked to, or loaded
 if( ${_OPT}use_ffmpeg STREQUAL "off" )
    message( STATUS "Disabling '${name}' library" )
 else()

cmake-proxies/lame/config.h.in

@@ -19,7 +19,7 @@
 /* Define to 1 if using `alloca.c'. */
 #cmakedefine C_ALLOCA 1
 
-/* alot of debug output */
+/* a lot of debug output */
 #cmakedefine DEBUG 1
 
 /* allow to compute a more accurate replaygain value */
@@ -286,7 +286,7 @@
 /* Define to 1 if you can safely include both <sys/time.h> and <time.h>. */
 #cmakedefine TIME_WITH_SYS_TIME 1
 
-/* faster log implementation with less but enough precission */
+/* faster log implementation with less but enough precision */
 #cmakedefine USE_FAST_LOG 1
 
 /* Enable extensions on AIX 3, Interix.  */