Add operator new[]/delete[] overloading and fix a memory leakage bug in association rule

Pivotal ID: 56750392
Documentation: Reformat all docs to reflect new style sheet

All documenation, except ones in Early Stage Development have been updated
to the new improved style sheet.
Cox Proportional Hazards: Add stratification support

Pivotal Tracker: 55945460

Other authors:
    Feng, Xixuan (Aaron) <xfeng@gopivotal.com>
    Shengwen Yang <syang@gopivotal.com>
    Rahul Iyer <riyer@gopivotal.com>

All Changes:
    - Updated Cox interface and changed function name to coxph
    - Added strata and optimizer_params parameters
    - Moved all help messaging to Python
    - Optimized the overall process (remove the intermediate step)
    - Replace plpgsql with sql for the overloaded functions
    - Implement stratified cox
    - Added Hessian to Cox Output Table
    - Added <output_table>_summary containing model details and its usage message
Cox Proportional Hazards: Add function for PH assumption test

Pivotal Tracker: 55945460

Other authors:
    Shengwen Yang <syang@gopivotal.com>
    Qian, Hai <hqian@gopivotal.com>
    Feng, Xixuan (Aaron) <xfeng@gopivotal.com>

All changes:
    - Added aggregate to compute Schoenfeld residual, element-wise correlation,
    and chi-square/p-values
    - Merged the design doc for stratified Cox including the residual
    computation part and chi-square computation
    - Changed function names
        coxph --> coxph_train
        zph --> cox_zph
Documentation: Improve formating for various modules

Changes:
    - Reformat doc in Early Stage Development modules to new template.
    - Treat online help consistently
        1. Remove from contents
        2. Remove online help section
        3. Make online help as the first step in examples
    - Remove group from SVDMF to eliminate it from docs
    - Change incorrect title in SVD documentation
Correct coxph train function to call coxph_train
Handle NULL values in input table gracefully

Pivotal Tracker: 57193570

Other authors:
        Feng, Xixuan (Aaron) <xfeng@gopivotal.com>
        Qian, Hai <hqian@gopivotal.com>
        Rahul Iyer <riyer@gopivotal.com>

All changes:
    - Implemented the NULL handling capability like R's na.oimit
    - Added num_rows_processed and num_missing_rows_skipped in the result table
    - Added more install-check cases
    - Can handle the case when all rows in the input table have NULL values
Added NULL handling in Linear Regression

* Moved all SQL code into Python
* NULL handling
Cox Proportional Hazards: Edit documentation to maintain consistency
Upgrade: Add script to upgrade to v1.3 from v1.0, v1.1, v1.2

Pivotal Tracker: 57615140

Changes:
    - Added all changelist files to upgrade to v1.3
    - Updated script to new upgrade
    - Fixed issues around whitespace between arguments
    - Release notes for v1.3
    - Updated version numbers
    - Update PGXN versioning style to accomodate requirements
Fixed signed vs size_t comparison warning (yyleng)

All current available versions (from 2.5.33 to 2.5.37) of flex declare yyleng as int instead of size_t.
Documentation: Remove TOC links to non-existent sections.

Updates in following modules:
    - Logistic regression
    - Cross validation
Clustered variance: Fix issues with incorrect casting

Pivotal Tracker: 58728080

Changes:
    - Fix integer to boolean cast bug in clustered variance for logistic regr
    - Fix missing drop cast to allow multiple madlib schemas in DB
Linear/logistic: Add explanation for p-values being zero instead of epsilon

Pivotal Tracker: 58728080

Probablilty values computed on a finite-precision machine can sometimes to be
too low. In such cases, we usually threshold the value and print it as 'zero'.
For statisticians, this has a different meaning that saying '< epsilon'.
We acknowledge this by adding a note in the documentation.
Cox Prop Hazards: Add NULL Handling

Pivotal Tracker: 57195006

Changes:
    - Added NULL Handling to allow NULLS in independent and dependent variable
    - Added 'num rows processed' and 'num rows skipped' values in summary table
    - Ensured that zph residual skips over NULL value rows while computing the
    residual statistic
fixed array ops (checking types before using)
Fix the incompatibility with GPDB4.3 w/ ORCA

Pivotal Tracker: 57198180

LDA is not compatible with ORCA in GPDB 4.3. To avoid performance
regression, the only workaround now is to temporarily turn off ORCA
when executing LDA.
GPPKG: Change generated gppkg name

Naming conventions for GPPKG have been changed to enable easy detection of
open-source software version number. The change is required since 'gppkg'
performs installation/uninstallation using the gppkg name.
LDA: Turn off optimizer only when GPDB is 4.3

Pivotal Tracker: 58839874

Commit 14e2d74 added a fix for LDA by turning-off ORCA. The commit, however,
didn't add a check for GPDB 4.3 and hence led to issues with postgres and GPDB
4.1 and 4.2. This commit fixes that problem by checking if the GPDB version
is specifically 4.3 before turning the optimizer off.
LDA: Remove notice statements