### 1.14
* corrected issue in frailty.fit function for option GE
* option JSW (Jorgensen-Seshadri-Whitmore) was added in frailty.fit function

### 1.13
* option GE (generalized exponential) was added in frailty.fit function

### 1.12

* corrected the frailty variance for the MIG and MBS models

### 1.11

* corrected the observed log-likelihood function for the MIG model
* option MBS (mixture of Birnbaum-Saunders) was added in frailty.fit function

### 1.10

* corrected the variance of frailty for the MIG model and its estimated standard error

### 1.9

* option MIG (mixture of inverse gaussian) was added in frailty.fit function

### 1.8

* removed dependency of frailtypack package

### 1.7

* option TN (truncated normal) was added in frailty.fit function

### 1.6

* fixed bugs in summary.extrafrail function to compute p-values

### 1.5

* option exp (exponential) was added in frailty.fit function as baseline model
* fixed bugs in summary.extrafrail function for pe distribution as baseline model

### 1.4

* option pe (piecewise exponential) was added in frailty.fit function as baseline model

### 1.3

* option BS (Birnbaum-Saunders) was added in frailty.fit function

### 1.2

* fixed bugs in summary.extrafrail function

### 1.1

* function frailtyWL was deprecated
* function frailty.fit was included. Besides the shared weighted Lindley frailty model, this
  function allows to perform estimation for the shared gamma and shared inverse gaussian frailty 
  models.

