update readme

README.md

 # seispy
 
 [![pipeline status](https://git.nju.edu.cn/geophy/seispy/badges/master/pipeline.svg)](https://git.nju.edu.cn/geophy/seispy/commits/master)
-[![coverage report](https://git.nju.edu.cn/geophy/seispy/badges/master/coverage.svg)](https://git.nju.edu.cn/geophy/seispy/commits/master)
 [![LGPLv3](https://www.gnu.org/graphics/lgplv3-88x31.png)](https://www.gnu.org/licenses/lgpl.html)
 
 Python module of seismology and  receiver functions
 
 # Installation
 ## Dependencies
-  * [obspy](http://docs.obspy.org)<br />
-  * [GMT 5.x](http://gmt.soest.hawaii.edu)<br />
+  * [Python]() >= 3.6
+  * [ObsPy](http://docs.obspy.org) >= 1.1.0
+  * [NumPy](http://www.numpy.org/) >= 1.14
+  * [SciPy](http://www.scipy.org/) >= 1.2.0
+  * [matplotlib](https://matplotlib.org/) >= 3.0.0
+  * [PyQt5](https://www.riverbankcomputing.com/software/pyqt/)
   
 ## Installation
 ```Python
@@ -18,7 +21,17 @@ python setup.py install
 
 # Inclusion
 --------------
-  * seispy.distaz: Calculate distance and azimuth (by [the lithospheric seismology program at USC](http://www.seis.sc.edu/software/distaz/)).<br />
-  * seispy.geo: Tiny codes of geophysics.
-  * seispy.bootstrap: Bootstrap confidence interval estimation (by [scikits-bootstrap](https://github.com/cgevans/scikits-bootstrap))
-  * seispy.decov: Iterative time domain deconv using Ligorria and Ammon's 1999 BSSA method
+## Libraries
+  * `seispy.distaz`: Calculate distance and azimuth (by [the lithospheric seismology program at USC](http://www.seis.sc.edu/software/distaz/)).<br />
+  * `seispy.geo`: Tiny codes of geophysics.
+  * `seispy.bootstrap`: Bootstrap confidence interval estimation (by [scikits-bootstrap](https://github.com/cgevans/scikits-bootstrap))
+  * `seispy.decov`: Iterative time domain deconv using Ligorria and Ammon's 1999 BSSA method
+
+## Commands
+ * `pickrf`: Pick PRFs after the calculation.
+ * `plotrt`: Plot PRFs in R and T components order by back-azimuth.
+ * `plotr`: Plot PRFs in R component order by back-azimuth.
+ * `hk`: H-Kappa stacking.
+ * `rf2depth`: Convert PRFs to depth axis.
+ * `ccp_profile`: CCP stack PRFs along a profile.
+