Fix $t_path on windows

Backported from master e7ee768d97e078a1a669ba6279671e58e9936ba8

Signed-off-by: Damien Regad <damien.regad@merckgroup.com>
Streamline $g_path definition

Simplify the code by replacing uses of ternary operator with switch
statement and removing unnecessary variable assignments.

We now also cover the (admittedly unlikely) scenario where the
temporary path is empty, to ensure we always generate a valid path
that includes a trailing '/'.
Localisation updates from http://translatewiki.net.
Whitespace fixes
Custom fields names in Excel export were converted to lower case

This was not happening in other export functions; the root cause was
inconsistent code to output the column headers in the excel API.

Function excel_get_titles_row() now relies on column_get_title() to
retrieve the custom fields default name, same as standard columns, and
in line with CSV export.

Fixes #14772
Whitespace fixes
Fix #9159: Added missing CSS 'button' class
Custom fields api - optimize and use db_query_bound

Replaces all uses of db_query() by db_query_bound() in the API.

Some SQL queries were rewritten in a cleaner and more efficient way.

custom_field_update() was greatly simplified by use of a foreach loop
instead of nearly identical code blocks for processing of each field to
update.

Fixes #14765, #14766
Don't display custom fields from disabled projects in view issues page

SQL for ALL_PROJECTS in custom_field_get_linked_ids() function was
modified to filter out disabled projects.

Thanks to vibe972 who originally submitted a patch for this on Github.
Original commit was rewritten due to changes made to the API.

Fixes #14764
Improve custom fields error messages

Introduce an additional 'Invalid Custom Field property' error message
that includes the name(s) of the properties which failed validation when
attempting to update the custom field.

Note: skip error message number 1305 to maintain forward-compatibility
with constants as they are defined in master branch

Fixes #14767
Use object properties instead of bug_get_field() calls
Whitespace fixes
Fix issue in tag api with odbc_mssql driver

This branch of code was put into place to handle a deficiency in the
odbc_mssql driver that doesn't allow for bound subqueries. This is not
needed for the other mssql drivers, yet using db_is_mssql() returns true
for all mssql drivers so code is indiscriminately executed for other
drivers.

$t_params[] init was changed because it only needs to be set once. It is
needed for the query in the mssql condition block for the first query
only to grab the list of tags that aren't specific to this bug.
Afterwards in the second query, $t_params needs to be null or it results
in the database returning an error due to no '?' replacements.
Therefore, after running the first query, we need to set this to null.
If the condition fails and the dbtype is not mssql (or 'odbc_mssql')
then $t_params is already set.

Note: the multiple query setup in the "true" condition is a really bad
way to do this. I'm not going to mess with it, however, since the tag
count probably won't get too high in any general scenario.

Fixes #14774

Signed-off-by: Damien Regad <damien.regad@merckgroup.com>

Note, this was simply checked for syntax errors and compliance with
coding guidelines as I don't have access to an MSSQL setup.
Fix #13265: Issues count in Changelog

Prior to this, issues having multiple parents were counted more than
once, causing an incorrect count of issues to be reported (changelog
displayed the number of printed lines instead of the number of distinct
issues in the version)

This is an improvement over SL-Gundam's original patch, which did not
cover all cases.
Optimize and reformat code in changelog_page.php

- Remove unnecessary variable initializations
- Reformat SQL statement for better readability
- Simplify code displaying issue count
Change Log must consistently rely on fixed_in_version

Change Log used target_version instead of fixed_in_version to manage
issues' parent/child relationships. This caused unexpected behavior when
target version did not match fixed in version.

The SQL which retrieves the changelog issues now relies on
fixed_in_version.

Fixes #14788
Localisation updates from http://translatewiki.net.
Remove whitespace at beginning of english language file

Introduced by d8d3409acb97500c2861a4c6a9e6f9133e2568df - caused
regression on SOAP API
Support upgrade functions (i.e. non SQL steps) in plugin installs/upgrades

This seems to have been supported at one point but was no longer working.  ManTweet is a consumer of such functionality.
Whitespace changes, fix comment