build: adding updated notes for HISTORY/CHANGELOG
## Latest improvements ##
+## Improvements for v1.4.0 ##
+
+ * autotest
+ - automated code coverage testing (72%)
+ * build
+ - incorporated error handling in most methods with integer-based return value
+ * agc
+ - added interface to check if AGC is locked or not
+ * buffer
+ - cbuffer: added method to check if buffer is empty
+ * dotprod
+ - included methods to create/recreate object in reverse order
+ * equalization
+ - eqlms: added convenience methods for copying coefficients and running as
+ a decimator
+ * fft
+ - spgram: adding convenience methods for getting/setting properties
+ - spwaterfall: adding convenience methods for getting/setting properties
+ * filter
+ - new direct digital synthesis (DDS) family of objects which allows
+ cascaded half-band interpolation/decimation with arbitrary frequency
+ translation
+ - new fractional delay (fdelay) family of objects which allow for
+ adjustable large fractional delays
+ - firdecim: adding convenience method to get decimation rate
+ - firfilt: adding convenience methods to get/copy coefficients as well as
+ create object using firdespm algorithm
+ - firinterp: adding convenience methods for new ways to create object as
+ well as getting object properties
+ - firpfb: adding convenience methods to create default object, write
+ samples
+ - resamp2: adding methods to get/set output scale
+ - rresamp: adding methods to operate with block execution
+ * framing
+ - new arbitrary rate symstreamr object (derived from symstream family)
+ - framesync64: adding methods for getting/resetting frame data statistics
+ as well as getting/setting detection threshold
+ - gmskframegen/gmskframesync: extending methods to support easier
+ operation, getting/resetting frame data statistics, more control over
+ parameters in create methods
+ - ofdmflexframesync: adding methods to get/reset frame data statistics
+ - qdetector: adding method to get threshold
+ - qpilotsync: adding method to get error vector magnitude
+ - symstream: adding convenience methods for getting properties
+ - symtrack: adding convenience methods for getting/setting properties
+ * math
+ - adding `liquid_` prefix to winodowing functions while supporting backwards
+ compatibility with older methods
+ - adding `liquid_` prefix to internal polynomial functions, using
+ common double-precision method for finding polynomial roots
+ * multichannel
+ - firpfbch2: adding convenience methods to get object properties
+ * modem
+ - modem: adding type extension for more consistency: `modem` -> `modemcf`,
+ supporting backwards compatibility with API shim
+
## Improvements for v1.3.2 ##
* autotest
